ALBERT

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Li Zhang, Xuanfeng Yue, Nan Li, Hailan Shi, Jing Zhang, Zhiqi Zhang, Fuquan Dang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Magnetic nanoparticles (MNPs) have been widely explored in enrichment of low-abundance glycoproteins/glycopeptides prior to mass spectrometry analysis in glycoproteomics. Currently, most functional groups for recognizing glycoproteins/glycopeptides are usually immobilized on the nanomaterial surface based on covalent modification, which suffers from multistep treatment, surface-dependence, and harsh conditions. In this work, we first report a facile and rapid method for surface functionalization and subsequent glycopeptides enrichment via one-step assembly of maltose-modified oligopeptides with a sequence of Ala-Glu-Ala-Glu-Ala-Lys-Ala-Lys (AEK8-maltose). In physiological conditions, AEK8-maltose readily self-organized into a complete coating layer dominated by β-sheets on the surface of SiO〈sub〉2〈/sub〉@Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 and C@Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 MNPs, which remain intact to repeat washing with acidic organic and aqueous solutions extensively used in the sample enrichment treatments. Thus, the resulting AEK8-maltose functionalized MNPs show excellent performance in enrichment of glycopeptides in standard glycoprotein digests (24 glycopeptides from horseradish peroxidase (HRP), 31 glycopeptides from immunoglobulin (IgG)) and human serum digests (282 glycopeptides), including rapid enrichment speed (5 min), high detection sensitivity (0.001 ng/μL HRP), high selectivity (mass ratios of HRP and bovine serum albumin (BSA) digests up to 1:150), good enrichment recovery (over 86.3%), remarkable stability (repeatable for more than 8 times), and excellent renewability, which are better than or comparable with the literature results reported to date. The current work based on self-assembling oligopeptides provides a mild, economic and nontoxic procedure for one-step surface functionalization of various nanomaterials.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S000326701930981X-fx1.jpg" width="354" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 30 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Long Li, Yankun Peng, Yongyu Li, Fan Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Physical properties such as particle size distribution and compactness have significant confounding effects on the spectral signals of complex mixtures, which multivariate linear calibration methods such as partial least-squares (PLS) cannot effectively model or correct. Therefore, these effects significantly deteriorate calibration models’ predictive abilities for spectral quantitative analysis of complex mixtures. Here, new scattering correction methods were proposed to estimate the additive and multiplicative parameters considering light scattering effects in each spectrum and hence mitigate the detrimental influence of additive and multiplicative effects on quantitative spectroscopic analysis of complex mixtures. Three different correction methods were proposed to estimate the addition coefficient based on two different underlying assumptions, namely, whether this coefficient is related to the wavelength. After addition coefficient elimination, the multiplicative parameter can be eliminated by a simple but very efficient spectral ratio method. Furthermore, linear models are built with key variables, and the predictive performance of these models is verified using the root-mean-square error of prediction datasets. The proposed methods were tested on one apple data set and two publicly available benchmark datasets (i.e., near-infrared spectral data of meat and powder mixture samples) and compared with some existing correction methods. The results showed that (1) additive effects of different types of samples can be eliminated by different methods and (2) these methods can appreciable improve quantitative spectroscopic analysis of complex mixture samples. This study indicates that accurate quantitative spectroscopic analysis of complex mixtures can be achieved through the combination of additive effect elimination and the spectral ratio method.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019310347-fx1.jpg" width="256" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Juan Zhang, Zhipeng Chen, Sheng Tang, Xiaogang Luo, Jiangbo Xi, Zhaolin He, Junxia Yu, Fengshou Wu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The dehydration reaction of tetraamino porphyrin and 4,4’-biphenyldicarboxaldehyde was performed for the synthesis of a novel covalent organic framework (COF), which was decorated on magnetic Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 to obtain core-shell structured Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@COFs nanospheres for the first time, for effective extraction and enrichment of sulfonamides (SAs). The morphology and structure of the synthesized nanospheres were characterized through various methods. The extraction conditions for six SAs including sulfadiazine, sulfamerazine, sulfamethazine, sulfamonomethoxine, sulfamethoxazole, sulfadimethoxine were systematically optimized. Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@COFs nanospheres were evaluated for magnetic solid-phase extraction. By coupling with high-performance liquid chromatography, a facile and sensitive method was established for the quantitation analysis of six SAs. The method showed good linearity ranging from 1 to 500 ng mL〈sup〉-1〈/sup〉 with R〈sup〉2〈/sup〉〉0.99, high sensitivity with LODs in the range of 0.2-1 ng mL〈sup〉-1〈/sup〉, and high precision with RSDs≤6.3%. This method was further applied into determination of SAs in environmental water and food samples, with recoveries in the range of 65.3%-107.3% and RSDs≤6.7%. These successful applications suggest that the core-shell structured Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@COFs nanospheres could be used as a potential adsorbent for efficient extraction and analysis of trace SAs.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019310335-fx1.jpg" width="265" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 30 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Lei Meng, Chengwu Lan, Zhonghu Liu, Na Xu, Yuqing Wu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉It is of great importance to detect chlorotetracycline (CTC) in a highly sensitive and specific way because of its wide distribution in aquaculture and animal husbandry. Herein, we propose a novel ratiometric fluorescence strategy to assay CTC by using bovine serum albumin stabilized gold nanoclusters (BSA-AuNCs). The BSA-AuNCs consisting of 25 gold atoms (Au〈sub〉25〈/sub〉NCs) display a red emission at 640 nm (〈em〉λ〈/em〉〈sub〉ex〈/sub〉 = 370 nm). In the presence of CTC, a new blue emission at 425 nm is emerged and its intensity dramatically increases with the addition of more the analyte; meanwhile the red emission at 640 nm shows a linear decrease reversely. However, at identical conditions neither the analogues of CTC as tetracycline (TC), oxytetracycline (OTC) or doxycycline (DC) induces similar response of BSA-AuNCs. Such interesting phenomenon is proven related to the conversion from large Au〈sub〉25〈/sub〉NCs to smaller nanoclusters composing 8 gold atoms (Au〈sub〉8〈/sub〉NCs), which intrinsically originate from the interaction between CTC and the ligand BSA. Therefore, a ratiometric probe is established to sensitively detect CTC in the wide range (0.2–10 μM) with a low limit of detection (LOD) at 65 nM. In addition, this strategy can also be applied to assay CTC in human serum, showing great promise for practical applications in future.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019310323-fx1.jpg" width="489" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 21 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Afsaneh Mollahosseini, Yousef Elyasi, Mohammad Rastegari〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A polyacrylonitrile (PAN)/polydimethylsiloxane (PDMS) flat membrane was fabricated by electrospinning technique and modified using titanium dioxide (TiO〈sub〉2〈/sub〉) nanoparticles and low-energy materials, dimethyldichlorosilane (MeSiCl〈sub〉2〈/sub〉)/methyltrichlorosilane (MeSiCl〈sub〉3〈/sub〉), to obtain a hydrophobic surface. The new membrane was utilized for the electromembrane extraction (EME) of model molecules including dibutyl phthalate (DBP) and bis[2-ethylhexyl] phthalate (DEHP). The parameters affecting proposed EME were optimized by the response surface methodology (RSM) based on the central composite design (CCD). The optimized values were 200 V of voltage, 20 min of extraction time, 1100 rpm of agitation rate, 10 mL of donor phase volume and 1 mL of acceptor phase volume. From the results, the performance of EME with the new (modified) membrane remained almost constant after ten extraction cycles while the extraction performance of unmodified EME steeply fell after six extraction cycles. The limits of detection (LODs) for DBP and DEHP were 7.40 and 0.08 ng mL〈sup〉-1〈/sup〉, respectively. The linear dynamic range (LDR) was in the range of 100 to 4000 ng mL〈sup〉-1〈/sup〉 for DBP and 1 to 2000 ng mL〈sup〉-1〈/sup〉 for DEHP. The relative standard deviations (RSDs) were below 10%, and the relative recoveries were over 86%. The overall energy consumption for the extraction of the model molecules by new EME was 13.4 kWh m〈sup〉-3〈/sup〉. The approach is time-efficient and cost-effective, as the fabricated membrane has better reusability than the previous membranes used for EME.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309912-fx1.jpg" width="330" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 21 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Hui He, Zhanchen Guo, Yanrong Wen, Shuxin Xu, Zhen Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Laser desorption ionization mass spectrometry (LDI-MS) has been developed to be an essential tool for the analysis and identification of a large variety of species, ranging from small metabolites, drugs and pollutants to peptides and proteins and even to bacteria. Matrix assisted LDI-MS has shown a great power for macromolecules, but its analytical capability to low mass compounds is limited due to inherent drawbacks, including abundant interference in low mass range (〈800 Da) caused by matrix self-dissociation and poor reproducibility due to inhomogeneous crystallization. Several matrix-free methods have been developed to solve these issues, mainly through altering organic matrix with inorganic nanostructured surfaces or nanomaterials as LDI medium. In the past five years, improvements on conventional silicon-based, metal-based, metal oxide-based and carbon-based LDI media as well as emerging novel materials such as 2D nanomaterials and organic frameworks have gained important progresses. Meanwhile, with the deep research in light-matter interaction, LDI mechanism studies begin to grow and become to attach great importance. Advances in both medium and mechanism promote to expand the applicable potential of nanostructure/nanomaterial-assisted LDI-MS in many aspects, including trace analysis, structural analysis and MS imaging. In this review, we survey the major progresses in this area in recent years. We also sketch remaining challenges and directions for future development.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309894-fx1.jpg" width="398" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 21 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Ling Hao, Yuerong Zhu, Pingli Wei, Jillian Johnson, Amanda Buchberger, Dustin Frost, W. John Kao, Lingjun Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Mass spectrometry-based stable isotope labeling provides advantages of multiplexing capability and accurate quantification but requires tailored bioinformatics tools for data analysis. Despite the rapid advancements in analytical methodology, it is often challenging to analyze stable isotope labeling-based metabolomics data, particularly for isobaric labeling using MS/MS reporter ions for quantification. We report Metandem, a novel online software tool for isobaric labeling-based metabolomics, freely available at 〈a href="http://metandem.com/web/" target="_blank"〉http://metandem.com/web/〈/a〉. Metandem provides a comprehensive data analysis pipeline integrating feature extraction, metabolite quantification, metabolite identification, batch processing of multiple data files, online parameter optimization for custom datasets, data normalization, and statistical analysis. Systematic evaluation of the Metandem tool was demonstrated on UPLC-MS/MS, nanoLC-MS/MS, CE-MS/MS and MALDI-MS platforms, via duplex, 4-plex, 10-plex, and 12-plex isobaric labeling experiments and the application to various biological samples.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309870-fx1.jpg" width="457" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 20 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Qingqing Song, Jun Li, Yan Cao, Wenjing Liu, Huixia Huo, Jian-Bo Wan, Yuelin Song, Pengfei Tu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The principle of chromatographic fingerprint is that certain diagnostic metabolites should be always distributed in a given plant and currently, it has been widely accepted as a promising means for medicinal plant authentication. Moreover, the chemical profile is the only evidence to clarify the ingredients of those consumable plant products, 〈em〉e.g.〈/em〉 traditional Chinese medicine (TCM) prescriptions. Herein, efforts were made to describe the diagnostic metabolome of medicinal plant or TCM prescription using a binary code sequence. Forty-five well-known medicinal plants along with six relevant prescriptions were employed for concept illustration and proof. Each plant was subjected to chemical characterization, and diagnostic metabolites of all plants were gathered into a chemical pool containing 595 compounds. A robust method enabling the detection of all 595 constituents was then developed using LC coupled to scheduled multiple reaction monitoring. Analyst™ software was responsible for automatically judging the presence (defined as “1”) or absence (defined as “0”) of each analyte with a defined signal-to-noise threshold (S/N 〉 100). After converting each medicinal plant to a binary sequence consisting of 595 codes, an in-house database was built by involving all sequences. The potentials of sequence library retrieval towards plant authentication, preliminary chemical characterization, and deformulation of TCM prescriptions were demonstrated after that the diagnostic metabolome of each test sample was translated to a binary code sequence. Above all, binary code is a flexible tool for diagnostic metabolite sequencing of medicinal plants, and it should be an alternative tool of DNA barcoding towards plant authentication.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309808-fx1.jpg" width="383" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 20 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Øystein Skjærvø, Trine Grønhaug Halvorsen, Léon Reubsaet〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel 〈em〉all-in-one〈/em〉 paper-based sampling concept for mass spectrometric bottom-up protein analysis is here demonstrated in a chip format integrating instant immunocapture, protein reduction, - alkylation and tryptic digestion all 〈em〉in-device〈/em〉. Conventional laboratory grade filter paper was coated with the polymer 2-hydroxyethyl methacrylate-co-2-vinyl-4,4-dimethyl azlactone (pHEMA-VDM) with a subsequent covalent immobilization of the monoclonal antibody E27 targeting the biomarker human chorionic gonadotropin (hCG). 〈em〉In-device〈/em〉 protein reduction and alkylation was optimized with regards to reagent concentration and reaction pH. The sampling concept showed a high degree of performance between 10 and 1000 ng/mL (R〈sup〉2〈/sup〉 〉 0.99) by a five-point calibration curve sampled with hCG spiked to human serum samples and freshly collected whole blood samples, respectively. LOD (experimentally obtained at 100 pg/mL (2.64 pM/0.9 IU/L)) was demonstrated to be up to ten times lower with more than six times faster sample preparation than what has previously been reported for on-paper analysis of hCG in human serum samples.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309845-fx1.jpg" width="448" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 20 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Alistair K. Brown, Zhe Xia, Patrique Bulloch, Ifeoluwa Idowu, Olga Francisco, Jorg Stetefeld, Jake Stout, Jeff Zimmer, Chris Marvin, Robert J. Letcher, Gregg Tomy〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In response to the Canadian federal government's Cannabis Tracking and Licensing System compliance standards, a quantitative method was created for cannabis analysis, and validated using Eurachem V.2 (2014) guidelines. Cannabinol, cannabidiol, cannabigerol, cannabichromene, cannabidiolic acid, cannabigerolic acid, Δ-9-tetrahydrocannabinol, and Δ-9-tetrahydrocannabinolic acid A were all analysed by scheduled multiple reaction monitoring (MRM) via LC-MS/MS and isotope dilution. In addition, aflatoxins B1, B2, G1, and G2 were also analysed by scheduled MRM via LC-MS/MS and matrix matched calibration curves in order to achieve the reporting limits (≤2 μg kg〈sup〉−1〈/sup〉) set out by the European Pharmacopoeia. The LODs/LOQs were 0.50/1.7, 2.0/6.7, 0.59/2.0, and 0.53/1.8 μg kg〈sup〉−1〈/sup〉, for B1, B2, G1, and G2 respectively. Thirty one terpenes were analysed by selected reaction monitoring via GC-MS/MS and isotope dilution using β-myrcene-d〈sub〉6〈/sub〉 as a surrogate. All quantitative analyses can be accomplished using less than 1 g of material, with minimal solvent and consumable use, on low resolution instruments in less than 30 min of instrument time. Of important note is this method's power of selectivity, working ranges, and lack of need for extraction consumables such as SPE or QuEChERS, thereby minimising analytical costs and time.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309833-fx1.jpg" width="311" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 20 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Zidan Wang, Xufang Hu, Nianrong Sun, Chunhui Deng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Human serum is a huge bioinformatics database of human physiological and pathological state, many proteins/peptides among which can serve as biomarkers for monitoring human's health condition, thereby being worth exploring. The simple and fast capture of biomarkers from human serum is the first key step to realize their accurate detection. In this work, we developed the aptamer functionalized magnetic metal organic framework nanoprobe, and furtherly combined with mass spectrometry technology to establish an efficient method of identifying biomarkers. Taking insulin as example of biomarker in human serum, we developed sulfhydryl human insulin aptamer functionalized magnetic metal organic framework (denoted as Mag MOF@Au@HIA) through the post-synthetic modification of MIL-101(Cr)–NH〈sub〉2〈/sub〉 for testing the applicability of the established method. Depending on the strong magnetic responsiveness and high specific area as well as high-loaded human insulin aptamers, the limit of detection of insulin was down to 1 ng/mL and 2 ng/mL in the standard insulin solution and human serum, respectively. Moreover, a good linear relationship (R〈sup〉2〈/sup〉 = 0.998) was obtained by using standard insulin solution with concentration range from 100 ng/mL to 5 ng/mL, based on which the capture recovery of insulin with Mag MOF@Au@HIA from human serum was demonstrated to be excellent. All of the results indicate that the aptamer-functionalized magnetic metal organic framework is a promising nanoprobe for biomarkers capture in human serum.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉Mag MOF@Au@HIA was employed in detection of insulin from human serum combined with MALDI-TOF MS efficiently and sensitively.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309791-fx1.jpg" width="403" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 21 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Zhanmin Liu, Yanming Wang, Junhai Li, Yuanyuan Yuan, Xianyong Wu, Ruowen Liu, Youwei Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉For early detection and diagnosis of gastric cancer, a novel, highly sensitive detection of microRNA-378 was developed through rolling circle amplification and DNA-templated silver nanoclusters as a lable-free fluorescent probe. DNA-templated fluorescent silver nanoclusters (DNA/AgNCs) to make target signal cascade amplification were prepared and identified through their fluorescent spectrum. MiRNA-378 trigged rolling circle amplification to obtain the complementary sequence (cDNA) to combine with two DNA/AgNCs in the middle of a sandwich structure to induce the new fluorescent signal at a new wavelength. In the presence of microRNA-378, a large amount of RCA product cDNAs were hybridized with DNA/AgNCs as the fluorescence nanocluster beacon, resulting in fluorescence enhanced "turn-on" phenomenon. This study indicated that amplified fluorescence detection of microRNA-378 is a stable, low-cost, highly specific, and ultra-low as 1.07 fM detectability. The proposed approach of signal synergetic amplification facilitating the fluorescence detection microRNA shows great potential for potentially clinically diagnosis.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309936-fx1.jpg" width="304" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 21 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Hao-Hua Deng, Xiang-Yu Fang, Kai-Yuan Huang, Shao-Bin He, Hua-Ping Peng, Xing-Hua Xia, Wei Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Although numerous sensors have been successfully fabricated for the detection of various heavy metal ions by employing fluorescent gold nanoclusters (AuNCs) as nanoprobes, serious cross-interference often occurs when these ions coexist in samples, which results in glaring errors in quantification. In this study, glutathione-protected AuNCs (GSH-AuNCs) were synthesized and found to respond to both Cu〈sup〉2+〈/sup〉 and Hg〈sup〉2+〈/sup〉 via fluorescence suppression. Intriguingly, addition of Ag〈sup〉+〈/sup〉 to GSH-AuNCs could completely inhibit the quenching effect of Hg〈sup〉2+〈/sup〉 while not affecting the Cu〈sup〉2+〈/sup〉-mediated quenching process. Ag〈sup〉+〈/sup〉 can combine with Au〈sup〉+〈/sup〉 on the surface of AuNCs to form a strong Ag〈sup〉+〈/sup〉-Au〈sup〉+〈/sup〉 metallic bond, which disrupts the interaction between Hg〈sup〉2+〈/sup〉 and Au〈sup〉+〈/sup〉 and thus eliminates the corresponding quenching effect. Based on this phenomenon, a simple sensing approach for highly selective and sensitive detection of Cu〈sup〉2+〈/sup〉 in aqueous solution was developed using the GSH-AuNC/Ag〈sup〉+〈/sup〉 complex as a fluorescent turn-off nanoprobe. The proposed method exhibited good linearity in the concentration range 0.02–10 μM with a limit of detection of 12 nM. This assay was demonstrated to be suitable for determination of Cu〈sup〉2+〈/sup〉 in real water samples even in the presence of Hg〈sup〉2+〈/sup〉, showing great promise as a tool for assessment of environmental security and drinking water quality.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉Ag〈sup〉+〈/sup〉 can combine with Au〈sup〉+〈/sup〉 on the surface of gold nanoclusters to form a strong Ag〈sup〉+〈/sup〉-Au〈sup〉+〈/sup〉 metallic bond, which disrupts the interaction between Hg〈sup〉2+〈/sup〉 and Au〈sup〉+〈/sup〉 and thus eliminates the corresponding quenching effect. Based on this phenomenon, a simple sensing approach for highly selective and sensitive detection of Cu〈sup〉2+〈/sup〉 is developed.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309882-fx1.jpg" width="320" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 21 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Panagiota M. Kalligosfyri, Areti Sevastou, Iraklis K. Kyriakou, Sotirios S. Tragoulias, Despina P. Kalogianni, Theodore K. Christopoulos〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present report introduces the smartphone as a simple, low-cost detector/imager for chemiluminometric hybridization assays and quantitative competitive polymerase chain reaction (QCPCR). In QCPCR the amplification products from the target and the competitor DNA have identical sizes but differ in a short sequence flanked by the primers. The products are hybridized with their cognate oligonucleotide probes, captured on microtiter wells and detected via an enzyme-catalyzed chemiluminogenic reaction using the smartphone as a detector/imager. We provide, for the first time, data on: 〈em〉(a)〈/em〉 the detectability, analytical range and reproducibility of smartphone-based chemiluminometric hybridization assays of double stranded amplification products, 〈em〉(b)〈/em〉 the comparison of smartphone-based detection with a conventional digital camera and a luminometer, and 〈em〉(c)〈/em〉 the detectability, analytical range and reproducibility of smartphone-based QCPCR in terms of the number of copies of input target sequences in the sample prior to amplification. The limits of detection of the DNA hybridization assay based on the smartphone, digital camera and luminometer were 1.6, 2.4 and 1 pmol L〈sup〉-1〈/sup〉. Smartphone-based QCPCR showed an analytical range from 137 to 9x10〈sup〉5〈/sup〉 copies of target DNA.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309924-fx1.jpg" width="367" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 21 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Andrey Shishov, Elena Stolarova, Leonid Moskvin, Andrey Bulatov〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, a reversed-phase chromatomembrane extraction (RP-CME) method as a novel approach for automated sample pretreatment was suggested for the first time. The RP-CME was applied to automated separation of anions (formate, chloride, nitrate, phosphate and sulfate) from biodiesel samples as a proof-of-concept example. The novel design of chromatomembrane cell was developed for on-line RP-CME. The RP-CME procedure assumed mass-transfer of water-soluble analytes from organic sample phase (biodiesel sample) to aqueous phase supported in a porous composite mass-transfer block. The composite mass-transfer block based on microporous hydrophobic poly (tetrafluoroethylene) and hydrophilic glass fiber was developed for the RP-CME implementation. The block provided the effective retention of aqueous phase into the cell and simultaneous penetration of organic phase. The hydrophilic membrane-based sheet was used for the on-line separation of hydrophilic emulsion (biodiesel in water) containing target analytes obtained during analytes elution by aqueous phase from the mass-transfer block. The RP-CME was successfully coupled with an ion chromatography with conductivity detection. The limits of detection, calculated from a blank test based on 3σ, were 5 μg kg〈sup〉−1〈/sup〉 for sulfate, 6 μg kg〈sup〉−1〈/sup〉 for nitrate, 3 μg kg〈sup〉−1〈/sup〉 for chloride, 5 μg kg〈sup〉−1〈/sup〉 for phosphate and 1 μg kg〈sup〉−1〈/sup〉 for formate.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309729-fx1.jpg" width="270" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 20 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Peng-Fei Guo, Xi-Ming Wang, Meng-Meng Wang, Ting Yang, Ming-Li Chen, Jian-Hua Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The selective adsorption towards glycoproteins from complex biosamples is of vital importance in life science studies. A new zwitterionic hydrophilic material, i.e., a functionalized titanate nanosheet, is prepared by assembling well-dispersed gold nanoparticles (AuNPs) on the surface of ultrathin titanate nanosheets via an ion-exchange approach, followed through immobilizing 〈span〉l〈/span〉-cysteine (L-Cys) by Au-S bonding. This 2D-titanate-based zwitterionic hydrophilic material is shortly termed as L-Cys/Au/TiNSs and it exhibits transverse several hundred nanometers with an ultrathin nanosheet structure. The zwitterionic hydrophilic titanate nanosheets have strong adsorption affinity to glycoproteins, offering a large binding capacity towards immunoglobulin G (1098.9 mg g〈sup〉−1〈/sup〉), which could be readily stripped into an ammonium hydroxide (NH〈sub〉4〈/sub〉OH) solution (0.5%, m/v) with a recovery of 82.4%. The practical applications of L-Cys/Au/TiNSs are further proved by successful specific adsorption of IgG from human serum.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309821-fx1.jpg" width="248" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 1 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Hailee E. Anderson, Ines C. Santos, Zacariah L. Hildenbrand, Kevin A. Schug〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Beer is an incredibly complex beverage containing more than 3000 different compounds, including carbohydrates, proteins, ions, microbes, organic acids, and polyphenols, among others. Beer becomes even more complex during storage, for over time it may undergo chemical changes that negatively affect the flavor, aroma, and appearance. Thus, it can be expected that maintaining the quality of beer throughout its lifetime is a difficult task. Since it is such a popular drink throughout the world, being familiar with proper analytical techniques for beer evaluation is useful for researchers and brewers. These techniques include, but are not limited to, gas chromatography, liquid chromatography, matrix assisted laser desorption/ionization, capillary electrophoresis, mass spectrometry, ultraviolet–visible spectroscopy, and flame ionization detection. This review aims to summarize the various ingredients and components of beer, discuss how they affect the finished product, and present some of the analytical methods used for quality control and understanding the formation of chemicals in beer during the brewing process.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019308992-fx1.jpg" width="255" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1082〈/p〉 〈p〉Author(s): Zhengming Cao, Fenghe Duan, Xiaoyu Huang, Yang Liu, Nan Zhou, Lei Xia, Zhihong Zhang, Miao Du〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report herein a novel multiple electrochemical aptasensor based on covalent–organic framework (COF) for sensitive and simultaneous detection of miRNA 155 and miRNA 122, by using shell-encoded gold nanoparticles (Au NPs) as signal labels (AgNCs@AuNPs and Cu〈sub〉2〈/sub〉O@AuNPs, respectively, NCs = nanoclusters). A new COF nanowire was synthesized via condensation polymerization of 1,3,6,8-tetra(4-carboxylphenyl)pyrene and melamine (represented by TBAPy-MA–COF–COOH) for multiple aptasensor fabrication. The nanowire was then used as a platform for anchoring single-strand DNA (ssDNA), which was hybridized with the complementary aptamer (cApt) probes of miRNA 155 and miRNA 122. AgNCs@AuNPs and Cu〈sub〉2〈/sub〉O@AuNPs modified with cApts show separated differential pulse voltammetry (DPV) peaks at 0.08 and −0.1 V, respectively. The signal labels immobilized with cApts were released from the hybridized DNA complex and bound to their corresponding targets when contacting miRNAs. This phenomenon results in the substantial decline of the DPV peak current density of the signal labels. The developed TBAPy-MA–COF–COOH-based aptasensor has superior performance for sensing miRNA 155 and miRNA 122 simultaneously, with ultrasensitive low detection limits of 6.7 and 1.5 fM (S/N = 3), respectively, a wide linear range of 0.01–1000 pM, and high selectivity and applicability for serum samples. The proposed TBAPy-MA-based aptasensor demonstrates potential for simultaneous detection of multiple cancer biomarkers by replacing other ssDNA and aptamer strands.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉A new class multiple electrochemical aptasensor based on a novel covalent organic framework (COF) coupling with the shell-encoded gold nanoparticles (Au NPs) as signal labels was developed for sensitively detecting miRNA 155 and miRNA 122. The construction COF-based aptasensor exhibited low cross-reactivity, high sensitivity, good selectivity, and acceptable applicability in serum samples.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309006-fx1.jpg" width="282" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 13 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Jiao Zou, Jin-Gang Yu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A polyaminosaccharide (chitosan, CS) and an aminosaccharide 〈strong〉(〈/strong〉〈span〉d〈/span〉-galactosamine, GalN) were integrated together 〈em〉via〈/em〉 hydrothermal assembly to obtain a bis-aminosaccharides composite (CS-GalN), and a novel and facile chiral sensing platform based on CS-GalN modified glassy carbon electrode (CS-GalN/GCE) was fabricated and used for electrochemical recognition of tyrosine (〈em〉Tyr〈/em〉) enantiomers. CS-GalN composite was characterized by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and contact angle goniometry. It was observed that CS-GalN composite exhibited different binding ability for 〈em〉Tyr〈/em〉 enantiomers. Under optimized experimental conditions, the oxidation peak current ratio of L-〈em〉Tyr〈/em〉 to D-〈em〉Tyr〈/em〉 (I〈sub〉L〈/sub〉/I〈sub〉D〈/sub〉) and the difference between their peak potentials (ΔEp = E〈sub〉D〈/sub〉-E〈sub〉L〈/sub〉) were 1.70 and 28 mV at CS-GalN/GCE by square wave voltammetry (SWV). In addition, the peak currents increase linearly with the concentration of 〈em〉Tyr〈/em〉 enantiomers in the concentration range 0.01–1.00 mM with detection limits of 0.65 μM and 0.86 μM for L-〈em〉Tyr〈/em〉 and D-〈em〉Tyr〈/em〉 (S/N = 3), respectively. CS-GalN/GCE also exhibited the ability to determine the percentage of D-〈em〉Tyr〈/em〉 in the racemic mixture. In addition, CS-GalN/GCE possessed remarkable sensitivity, great stability as well as fine reproducibility. It could be concluded that the chiral interface of CS-GalN/GCE can provide an ideal platform for electrochemical recognition and determination of 〈em〉Tyr〈/em〉 enantiomers.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309456-fx1.jpg" width="280" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 14 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Imanuel Yüce, Milena Mayr, Gertrud E. Morlock〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉High-performance thin-layer chromatography (HPTLC) combined with 〈sup〉1〈/sup〉H nuclear magnetic resonance (NMR) spectroscopy has only been demonstrated over a small spectral range so far. The self-printing of chromatographic plates with a modified 3D slurry printer allowed the operator to influence the composition of the adsorbent slurry and thus the purity of the adsorbent layer. The combination of such self-printed, binder-free HPTLC plates with inkjet-driven sample application made possible submicromole-scaled analytical 〈sup〉1〈/sup〉H NMR spectroscopy. This was proven using pure HPTLC adsorbents. For comparison, commercial silica gel HPTLC plates were purified by pre-development with solvents for spectroscopy, whereas commercial silica gel HPTLC particles were self-printed on the glass plate after purification under solvent pressure in a recycled HPLC cartridge. Evaluating the signals from different treatments, seven background signals disappeared in the proton spectra and three were reduced to a minimum by use of pre-developed commercial HPTLC plates. In the case of the self-printed, binder-free HPTLC plates made of purified adsorbent, most of the spectral background signals were reduced to a minimum, thus these spectra showed the highest cleanness and most pure analyte proton spectra. For the first time, the full 〈sup〉1〈/sup〉H NMR spectroscopy range was made available after an HPTLC separation. This proof of principle opens the avenue for submicromole-scaled analytical 〈sup〉1〈/sup〉H NMR spectroscopy.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309407-fx1.jpg" width="383" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 8 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): J.A. Navarro-Huerta, E.J. Carrasco-Correa, J.R. Torres-Lapasió, J.M. Herrero-Martínez, M.C. García-Alvarez-Coque〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The development of methacrylate-based monolithic columns was studied for the separation of pharmaceutical hydrophilic compounds in nano-liquid chromatography. The selected polymerisation mixture consisted of 7.5% hexyl methacrylate, 4.5% methacrylic acid and 18.0% ethylene dimethacrylate (w/w), in a binary porogenic solvent (35:35 w/w 1-propanol/1,4-butanediol). The polymer synthesised with this mixture has a good permeability, not excessive back-pressure, and reasonable retention times for polar and non-polar solutes. Monolithic columns (12 cm total capillary length, 100 μm i.d.), prepared with this mixture, were able to produce hydrogen bonding and electrostatic interactions, giving rise to promising separations. To evaluate the chromatographic system, alkylbenzenes (neutral and hydrophobic compounds) and sulphonamides (hydrophilic drugs) were assayed. To optimise the chromatographic mobile phase in isocratic elution and characterise the retention mechanism for a mixture of eight sulphonamides, the performance of several mathematic models was checked in the description of retention. The behaviour of the monolithic capillary column was compared, in terms of selectivity and peak shape, to that obtained with a C18 column (9 cm × 4.6 mm i.d., 5 μm particle size) using a conventional HPLC equipment. The results revealed substantial differences in the interactions established for sulphonamides between the monolithic and C18 columns.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309419-fx1.jpg" width="232" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 8 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Zunmei Feng, Chuanhui Huang, Yuheng Guo, Ping Tong, Lan Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, oxygenated carbon nitride nanosheets (OCNNSs) were first introduced to the field of analytic chemistry for solid-phase microextraction (SPME). The rich hydroxyl and carboxyl contents of OCNNSs provided abundant adsorption sites. The coated stainless steel fibers, synthesized by the layer-by-layer chemical bonding method, had good chemical stability (in organic solvents), long life (durability ≥ 150 cycles), and good reproducibility (RSDs ≤ 9.2%). This novel OCNNSs-coated fiber was used for SPME with gas chromatography-mass spectrometry (GC-MS) for the analysis of phthalic acid esters (PAEs) in three types of food products (seafood, samshu, and instant noodles). Under optimal conditions, the limits of detection (LODs) for the PAEs ranged from 0.1 to 10.0 pg mL〈sup〉−1〈/sup〉, and recovery was in the range of 80.0–118.1%. These novel coated SPME fibers displayed excellent separation and enrichment properties, which suggest a pretreatment application for analysis of PAEs.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309420-fx1.jpg" width="409" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 6 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Rajalakshmi Sakthivel, Subbiramaniyan Kubendhiran, Shen-Ming Chen, Twe-Wei Chen, Nabil Al-Zaqri, Ali Alsalme, Fahad A. Alharthi, Maymonah M. Abu Khanjer, Tien-Wen Tseng, Chih-Ching Huang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Benefiting from the rich redox chemistry, high electrical conductivity and synergistic effect from two metal ions, the binary metal sulphides received tremendous attention in various applications. As a result, the MoS〈sub〉2〈/sub〉–RuS〈sub〉2〈/sub〉 nanomaterial was synthesized through the simple one-pot hydrothermal technique. The electrocatalytic activity of the as-synthesized nanomaterial was exploited towards the electrochemical detection of antibiotic drug sulphadiazine (SDZ). The electrocatalytic oxidation of the SDZ exhibited lowest anodic peak potential and ehanced anodic peak current rather than other modified electrodes. Notably, an excellent electrochemical performance with very lowest limit of detection (LOD) of 0.004 μM, appreciable linear range from 0.01 μM to 598.7 μM and high sensitivity (2.333 μA μM〈sup〉−1〈/sup〉 cm〈sup〉−2〈/sup〉) was obtained at MoS〈sub〉2〈/sub〉–RuS〈sub〉2〈/sub〉 modified electrode. Moreover, well anti-interfering property, good operational stability, repeatability and reproducibility was achieved. Facinatingly, the practicability of the modified electrode demonstrated in milk and human serum samples.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309195-fx1.jpg" width="393" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 6 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Waleed Alahmad, Puttaruksa Varanusupakul, Takashi Kaneta, Pakorn Varanusupakul〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉In this study, we developed and compared three different methods for chromium speciation in water samples using microfluidic paper-based analytical devices (μPADs). In all methods, detection was based on the complexation reaction of Cr(VI) with diphenylcarbazide on the μPADs. Cr(III) ions were oxidized to Cr(VI) by Ce(IV) prior to colorimetric detection on the μPADs. In the first method, oxidization of Cr(III) to Cr(VI) in the solution containing both trivalent and hexavalent chromium was performed using a batch procedure to obtain total chromium. A dual electromembrane extraction (DEME) technique for simultaneous preconcentration and extraction of chromium species and a single electromembrane extraction (SEME) for preconcentration and extraction of Cr(VI)/total chromium [quantified as Cr(VI) content after oxidation of Cr(III) ions to Cr(VI)] were used in the second and third methods, respectively. The electromembrane extraction was based on the electrokinetic migration of cationic Cr(III) and anionic Cr(VI) toward the cathode and anode, respectively, into the two different hollow fibres. Octanol-1 and bis(2-ethylhexyl) phosphate (DEHP) in octanol-1 (0.7% v/v) were the most suitable supported liquid membranes for extraction of Cr(VI) and Cr(III), respectively. Among these methods, SEME showed the lowest limits of detection for both analytes.〈/p〉 〈p〉Under optimized conditions, linear calibrations were obtained for Cr(III) from 3 to 30 μg L〈sup〉−1〈/sup〉 and for Cr(VI) from 3 to 70 μg L〈sup〉−1〈/sup〉. The detection limits were 1.0 μg L〈sup〉−1〈/sup〉 and 0.7 μg L〈sup〉−1〈/sup〉 for Cr(III) and Cr(VI), respectively. Our developed method was applied to analyse water samples spiked with different concentrations of Cr(III) and Cr(VI) at the parts-per-billion (ppb) level. The statistical evaluation showed that the proposed method agreed well with the validation method, i.e., inductively coupled plasma atomic emission spectroscopy (ICP-AES).〈/p〉 〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309146-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 4 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1079〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: 4 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1079〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: Available online 1 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Kolsoum Dalvand, Alireza Ghiasvand〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Polyaniline silica (Silica/PANI) organic-inorganic nanocomposite was synthesized by combining electrospinning and in-situ polymerization processes. This strategy prevented the aggregation of PANI during the polymerization and led to higher synthesis's yield and more uniformity of the produced composite. The structure and morphology of the nanocomposite was characterized using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques. The prepared nanocomposite was then packed inside a stain-steel needle and evaluated as a needle trap device (NTD), for simultaneous headspace extraction of polycyclic aromatic hydrocarbons (PAHs) and benzene, toluene, ethylbenzene, and xylenes (BTEX) in polluted soil samples, before GC-FID analysis, as a low-cost and robust detector. Response surface methodology (RSM) involving Box-Behnken design (BBD) was implemented to evaluate the effective experimental variables and subsequent introduction of a multiple function to describe the experimental conditions for the extraction of the analytes. Wide calibration plots (1-2000 ng g〈sup〉−1〈/sup〉 for BTEX and 0.2–2000 ng g〈sup〉−1〈/sup〉 for PAHs) with acceptable linearity (R〈sup〉2〈/sup〉 〉 0.99) were obtained under the optimal conditions. The limits of detection were found to be 0.02–0.1 ng g〈sup〉−1〈/sup〉for BTEX and 0.001–0.01 ng g〈sup〉−1〈/sup〉 for PAHs. The calculated standard deviations were 7.3–13.2% (n = 6). The developed NTD-GC-FID method was successfully applied for the extraction and determination of PAHs and BTEX in contaminated soil samples.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309018-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 2 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Jin-Biao Liu, Chun Wu, Feng Chen, Chung-Hang Leung, Dik-Lung Ma〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A series of iridium(III) dimers were synthesized and their ability to interact with diethyldithiocarbamate for CS〈sub〉2〈/sub〉 sensing was evaluated. Upon the addition of CS〈sub〉2〈/sub〉, diethylamine can capture CS〈sub〉2〈/sub〉 to form diethyldithiocarbamate, which could chelate with the iridium(III) dimer to form a diethyldithiocarbamate iridium(III) complex, resulting in a yellow luminescence. Dimer 〈strong〉8〈/strong〉 exhibited a maximum 18-fold of luminescence enhancement upon the addition of CS〈sub〉2〈/sub〉. The luminescence signal of the detection system could be readily distinguished from the highly fluorescent media using time-resolved emission spectroscopy (TRES). The capability of the system to determine CS〈sub〉2〈/sub〉 level in water samples was also demonstrated.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉Iridium(III) dimer can interact with diethyldithiocarbamate for CS〈sub〉2〈/sub〉 sensing. Dimer 〈strong〉8〈/strong〉 exhibited a maximum 18-fold of luminescence enhancement upon the addition of CS〈sub〉2〈/sub〉. The luminescence signal of the detection system could be distinguished from the highly fluorescent media using TRES. The determination of CS〈sub〉2〈/sub〉 in water samples was also demonstrated.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309080-fx1.jpg" width="374" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 2 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Pabudi Weerathunge, Bijay Kumar Behera, Sabna Zihara, Mandeep Singh, Sanjana Naveen Prasad, Sabeen Hashmi, Pyria Rose Divina Mariathomas, Vipul Bansal, Rajesh Ramanathan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉With growing environmental and health concerns over persistent organic compounds such as organophosphates, regulatory bodies have imposed strict regulations for their use and monitoring in water bodies. Although conventional analytical tools exist for the detection of organophosphorus pesticides, new strategies need to be developed to fulfil the ASSURED (affordable, sensitive, specific, user-friendly, rapid, equipment-free and deliverable to end users) criteria of the World Health Organisation. One such strategy is to employ the ability of certain nanoparticles to mimic the enzymatic activity of natural enzymes to develop optical sensors. We show that the intrinsic peroxidase-mimic NanoZyme activity of tyrosine-capped silver nanoparticles (Ag-NanoZyme) can be exploited for highly specific and rapid detection of chlorpyrifos, an organophosphorus pesticide. The underlying working principle of the proposed aptasensor is based on the dynamic non-covalent interaction of the chlorpyrifos specific aptamer (〈em〉Chl〈/em〉) with the NanoZyme (sensor probe) 〈em〉vs〈/em〉. the pesticide target (analyte). The incorporation of the 〈em〉Chl〈/em〉 aptamer ensures high specificity leading to a colorimetric response specifically in the presence of chlorpyrifos, while the sensor remains unresponsive to other pesticides from organophosphate and non-organophosphate groups. The robustness of the sensor to work directly in environmental samples was established by evaluating its ability to detect chlorpyrifos in river water samples. The excellent recovery rates demonstrate the sensor robustness, while the simplicity, and rapid sensor response (2 min) to detect the presence of chlorpyrifos highlights the capabilities of the proposed colorimetric sensing system.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309043-fx1.jpg" width="260" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 1 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Manjie Gao, Qifeng Fu, Min Wang, Kailian Zhang, Jing Zeng, Lujun Wang, Zhining Xia, Die Gao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Novel porous covalent organic frameworks (COFs) were synthesized via a facile approach at room temperature by using 1,3,5-tris(4-aminophenyl)benzene and 2,3,5,6-tetrafluoroterephthalaldehyde as two building blocks for the first time. And the COFs were applied as dispersive solid phase extraction (dSPE) adsorbents for the extraction of six nitroaromatic compounds (NACs) from diverse water samples. The COFs were characterized by scanning electron microscopy (SEM), energy dispersive spectrum (EDS), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), the nitrogen adsorption-desorption isotherms and Zeta potentiometric analysis. The results indicated that the COFs possessed high specific surface area, good thermal and chemical stability. Moreover, some parameters (including adsorbent dosage, extraction time, pH, ion strength, desorption solvent, desorption time and desorption frequency) which influenced the extraction efficiencies of NACs were investigated in details. By combining COFs-based dSPE with HPLC-DAD analysis, a simple, fast and effective method was developed for the extraction and determination of six NACs. The method demonstrated good linearity in the range of 0.01–50 μg mL〈sup〉−1〈/sup〉 (R 〉 0.9973) with low limits of quantification (0.1–0.25 μg mL〈sup〉−1〈/sup〉, S/N = 10) and low limits of detection (0.03–0.09 μg mL〈sup〉−1〈/sup〉, S/N = 3). Good precision with relative standard deviations (RSD) lower than 3.56% for intra-day and 4.78% for inter-day were also obtained. Finally, COFs-based dSPE was applied to the effective extraction of six NACs from three kinds of actual water samples, and good recoveries (ranged from 84.00 to 112.29%) were observed. These results demonstrated that the COFs had promising potential to be adsorbents for dSPE of NACs in complex samples.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309092-fx1.jpg" width="354" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 19 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Pieter Venter, Tim Causon, Harald Pasch, André de Villiers〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, we report a methodology based on reversed phase LC (RP-LC) and hydrophilic interaction chromatography (HILIC) separations coupled to ion mobility (IM) and high resolution mass spectrometry (HR-MS) for the detailed analysis of hydrolysable tannins. The application of this approach to the analysis of an industrial chestnut (〈em〉Castanea sativa〈/em〉, wood chips) tannin extract is demonstrated. A total of 38 molecular species, including a large number or isomers, were identified in this sample based on HR-MS〈sup〉(E)〈/sup〉 and UV absorption spectral information as well as retention behaviour in both separation modes. In total, 128 and 90 isomeric species were resolved by RP- and HILIC-LC-IM-TOF-MS, respectively. The combination of low- and high collision energy mass spectral data with complementary chromatographic separations allowed tentative and putative identification of twenty molecular species, comprising 78 isomers, in chestnut for the first time. Ion mobility resolved six new dimeric and trimeric vescalagin conformers with unique arrival (drift) times, including new conformers of roburin A-D which were not separated using either RP-LC or HILIC. HILIC was found to be the preferred separation mode for the analysis of vescalagin derivatives, while RP-LC is preferred for the analysis of ellagitannins with a cyclic glucose core. For the complete separation of the galloyl glucose species, comprehensive HILIC × RP-LC separation would be required.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S000326701930978X-fx1.jpg" width="366" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 17 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Yisen Liu, Songbin Zhou, Wei Han, Weixin Liu, Zefan Qiu, Chang Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Fusion of spectral and spatial information has been proved to be an effective approach to improve model performance in near-infrared hyperspectral data analysis. Regardless, most of the existing spectral-spatial classification methods require fairly complex pipelines and exact selection of parameters, which mainly depend on the investigator's experience and the object under test. Convolutional neural network (CNN) is a powerful tool for representing complicated data and usually works with few “hand-engineering”, making it an appropriate candidate for developing a general and automatic approach. In this paper, a two-branch convolutional neural network (2B–CNN) was developed for spectral-spatial classification and effective wavelengths (EWs) selection. The proposed network was evaluated by three classification data sets, including herbal medicine, coffee bean and strawberry. The results showed that the 2B–CNN obtained the best classification accuracies (96.72% in average) when compared with support vector machine (92.60% in average), one dimensional CNN (92.58% in average), and grey level co-occurrence matrix based support vector machine (93.83% in average). Furthermore, the learned weights of the two-dimensional branch in 2B–CNN were adopted as the indicator of EWs and compared with the successive projections algorithm. The 2B–CNN models built with wavelengths selected by the weight indicator achieved the best accuracies (96.02% in average) among all the examined EWs models. Different from the conventional EWs selection method, the proposed algorithm works without any additional retraining and has the ability to comprehensively consider the discriminative power in spectral domain and spatial domain.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309675-fx1.jpg" width="454" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 17 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Mingqian Wang, Ying Liang, Zhicheng Zhang, Guohong Ren, Yajun Liu, Shishan Wu, Jian Shen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Novel multifunctional core-shell nanoparticles (NPs) have attracted widespread attention due to their easy-to-modify surface properties and abundant functional groups. This study introduces a facile approach to synthesize Ag@ iron oxide (Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉) @C NPs, and modify with amino-poly (ethylene glycol) (PEG)-carboxyl and folate (FA) on the exposed carbon surface to produce high contrast for excellent stability, good biocompatibility, cancer cell targeting, and synergistic treatment. The multi-armed PEG at the edge of Ag@Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@C NPs provides the materials an excellent capacity for doxorubicin (DOX) loading. The carbon layer could be used as a photothermal reagent due to its excellent near-infrared (NIR) absorbance capacity, and Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 was used as a reagent for magnetic resonance (MR) imaging. 〈em〉In vivo〈/em〉 combination therapy with this agent was administered in a mouse tumor model, and a remarkable synergistic antitumor effect that is superior to that obtained by monotherapy was achieved. Concerning these features together, these unique multifunctional Ag@Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@C-PEG-FA/DOX NPs could be regarded as an attractive nanoplatforms for chemo-photothermal synergistic tumor therapy with dual-modal fluorescence and MR imaging-guided targeting.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉The chemical properties of Ag@Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@C-PEG-FA/DOX NPs was investigated, and the NPs was then used for 〈em〉in vivo〈/em〉 targeted FL/MR imaging and synergistic targeted therapy of tumor.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309766-fx1.jpg" width="373" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 17 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Jacek R. Wiśniewski〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Filter Aided Sample Preparation (FASP) is a widely used protein processing technique in “bottom-up” proteomics. Its popularity reflects the key features of the method: its applicability to a variety of sample types and the high quality of the released peptides. Successful application of FASP requires optimized properties of sample lysate and its amount, use of ultrafiltration units with membranes having large molecular mass cut-offs and well selected conditions for protein digestion. In contrast to the majority of sample preparation methods, FASP allows digestion of proteins with a variety of enzymes and a straightforward monitoring of protein-to-peptide conversion. A unique feature of FASP is the possibility to cleave proteins in a consecutive way using several proteases and to separate peptide fractions. Understanding principles of the method gives guidance in applying FASP to different types of samples in optimization of conditions of the FASP-workflow.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309730-fx1.jpg" width="420" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 17 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Daniel G. Horvath, Samuel Braza, Trevor Moore, Ching W. Pan, Lailai Zhu, On Shun Pak, Paul Abbyad〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Droplet microfluidics has the ability to greatly increase the throughput of screening and sorting of enzymes by carrying reagents in picoliter droplets flowing in inert oils. It was found with the use of a specific surfactant, the interfacial tension of droplets can be very sensitive to droplet pH. This enables the sorting of droplets of different pH when confined droplets encounter a microfabricated trench. The device can be extended to sort enzymes, as a large number of enzymatic reactions lead to the production of an acidic or basic product and a concurrent change in solution pH. The progress of an enzymatic reaction is tracked from the position of a flowing train of droplets. We demonstrate the sorting of esterase isoenzymes based on their enzymatic activity. This label-free technology, that we dub droplet sorting by interfacial tension (SIFT), requires no active components and would have applications for enzyme sorting in high-throughput applications that include enzyme screening and directed evolution of enzymes.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309663-fx1.jpg" width="337" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 13 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Ming Li, Lei Jiao, Siquan Liu, Lianhua Zhang, He Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Ratiometric signal transducing strategies can improve the precision of immunoassay, which possess the unique merits of spatial-resolved signal readout and self-correcting towards possible false positive results. In this work, a new ratiometric electrochemical immunosensor has been developed for reliable detection of Nuclear matrix protein 22 (NMP22). Bioinspired synthetic melanin nanospheres (SMNPs) were elaborately chosen for the following considerations: 1) SMNPs can supply good biocompatible biorecognition interface for antibody anchoring; 2) SMNPs can chelate a large amount of lead ions (Pb〈sup〉2+〈/sup〉) and copper ions (Cu〈sup〉2+〈/sup〉) to fabricate two spatial-resolved electrochemical signals with different response manners towards NMP22. SMNPs chelated with Pb〈sup〉2+〈/sup〉 were used for the immobilization of captured primary 〈em〉anti〈/em〉-NMP22. And SMNPs chelated Cu〈sup〉2+〈/sup〉 were employed to prepare signal labels after anchored with 〈em〉anti〈/em〉-NMP22 antibody. After sandwich-type immunoreaction, with the increasing concentration of NMP22, the stripping peak current of Pb〈sup〉2+〈/sup〉 decreases while the stripping peak current of Cu〈sup〉2+〈/sup〉 increases. Thus, ratiometric electrochemical signals could be provided for NMP22 detection. The immunosensor presented a linear concentration range from 0.013 U mL〈sup〉−1〈/sup〉 to 6.7 U mL〈sup〉−1〈/sup〉 with a limit of detection of 0.005 U mL〈sup〉−1〈/sup〉 towards NMP22. Meanwhile, satisfactory reproducibility, stability and selectivity of the immunosensor were demonstrated.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309444-fx1.jpg" width="368" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 8 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1080〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: 8 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1080〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: Available online 7 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Ruoxi Du, Mingzhang Guo, Xiaoyun He, Kunlun Huang, Yunbo Luo, Wentao Xu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Whole cell biosensors offer high potential for the detection of heavy metals in a manner that is simple, rapid and low-cost. However, previous researchers have paid little attention to the impacts of construction models on the performance of these biosensors, thereby limiting the achievement of rational design and the optimization of detection characteristics. Herein, for the first time, three basic models of lead and mercury detection circuits, namely feedback coupled, uncoupled and semi-coupled models, have been constructed and compared to explore the effects of uncoupling the topology of sensing circuits on the reporter signals. The results demonstrated that the uncoupled model had better sensitivity for both lead (50 nM) and mercury (1 nM), while the feedback coupled circuits had a wider detection range for mercury (10 nM - 7.5 μM). Introducing the semi-coupled model into the comparison revealed that both the type and location of promoters for regulatory protein genes were key factors for sensitivity. Moreover, the detection characteristics of the uncoupled biosensors were robust, as conditions such as induction time, the concentration of microbial cells, and the concentration of antibiotics had little interference on the performance of the microbial biosensors. This study also established a novel and simple pre-treatment method for sample detection by biosensors. When the uncoupled microbial biosensor was put into practice, the concentration levels of mercury in milk and lead in sewage were determined quickly and accurately. Our study, therefore, provides a strategy for the rational design of whole cell heavy metal biosensors and has developed the potential of their application.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309183-fx1.jpg" width="394" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 7 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Mingyuan Du, Ningxing Li, Guobin Mao, Yucheng Liu, Xinxin Wang, Songbai Tian, Qinxue Hu, Xinghu Ji, Yalan Liu, Zhike He〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The viral capsid protein p24 of human immunodeficiency virus is expressed at different level during viral invasion. Detection of p24 is of great importance in acquired immunodeficiency syndrome monitoring and therapy. A ratiometric probe that is easily-synthesized was constructed based on self-assembled fluorescent Ce(Ⅲ) and fluorescein. Fluorescein was used as reference. Hydrogen peroxide quenches the fluorescence of the Ce(III) easily but does not quench the fluorescence of fluorescein. The mechanism of reaction was discussed. Benefiting from the sensitive response to hydrogen peroxide, this probe was applied for p24 detection in enzyme linked immunoassay. The fluorescence ratio was in a good linear relationship with the concentration of p24, and the detection limit was 1.1 pg mL〈sup〉−1〈/sup〉. This proposed method has shown potential in virus detection with easy operation.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309237-fx1.jpg" width="300" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1082〈/p〉 〈p〉Author(s): Jiujiang Yan, Zhongqi Hao, Ran Zhou, Yun Tang, Ping Yang, Kun Liu, Wen Zhang, Xiangyou Li, Yongfeng Lu, Xiaoyan Zeng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The determination accuracy of alloying elements in high alloy steel is generally poor in laser-induced breakdown spectroscopy (LIBS) due to their matrix effect. To solve this problem, an image quantitative analysis (IQA) method was proposed and verified by determining nickel (Ni) in 17 stainless steel samples in this work. The results showed that the coefficient of determination (R〈sup〉2〈/sup〉) was increased from 0.9833 of a conventional spectrum quantitative analysis (SQA) method to 0.9996 of the IQA method, and the average relative error of cross-validation (ARECV) and root mean squared error of cross-validation (RMSECV) were decreased from 56.80% and 1.0818 wt% to 15.93% and 0.9866 wt%, respectively. Besides, the determinations of chromium (Cr) and silicon (Si) demonstrated the generalization ability of the IQA. This study provides an effective approach to improving the quantitative performance of LIBS through the combination of image processing and computer vision technology.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019308827-fx1.jpg" width="499" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 2 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Konrad Rudnicki, Lukasz Poltorak, Sławomira Skrzypek, Ernst J.R. Sudhölter〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, the electrochemical behavior of four fluoroquinolone antibiotics (〈em〉FAs〈/em〉) [Ciprofloxacin (〈em〉Cip〈/em〉), Enrofloxacin (〈em〉Enr〈/em〉), Marbofloxacin (〈em〉Mar〈/em〉) and Ofloxacin (〈em〉Ofl〈/em〉)] at a polarized interface between two immiscible electrolyte solutions (ITIES) has been studied using ion–transfer voltammetry (ITV). The measurements were conducted in the traditional macroscopic (macro-ITIES) and a recently developed miniaturized (micro-ITIES) platform. The latter was obtained from fused silica micro-capillaries having an internal diameter of 25 μm. We used macroITIES to obtain a number of analytical parameters such as: standard Galvani potential of ion transfer (ΔΦ〈sup〉0〈/sup〉), diffusion coefficients (〈em〉D〈/em〉), free Gibbs energy of ion transfer (Δ〈em〉G〈/em〉〈sup〉0〈/sup〉) and partition coefficients (logP〈sub〉DCE〈/sub〉). The latter were compared with the available literature values of logP〈sub〉octanol〈/sub〉. The effect of concentration of the studied antibiotics on the electrochemical response was investigated with the microITIES platform, setting statistical parameters such as: linear dynamic ranges (〈em〉LDRs〈/em〉 – studied from 1 μM up to 50 μM), lower limit of detections (〈em〉LODs〈/em〉 – around 1 μM) and sensitivity (found in the range from 2.6·10〈sup〉−2〈/sup〉 to 6.8·10〈sup〉−2〈/sup〉 nA·μM〈sup〉−〈/sup〉). MicroITIES were further used to study the effect of pH on the analytical signal and the results are plotted in a form of ion partition diagrams. Working with microITIES supported with the fused silica capillaries significantly reduced the volumes of consumed chemicals and expedite all analytical experiments. The provided results can be successfully applied in pharmacology and electroanalysis for testing and determination of the chosen fluoroquinolone antibiotics.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309031-fx1.jpg" width="261" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 3 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Yu Jiang, Jinjiang Cui, Tian Zhang, Mingyuan Wang, Guoxing Zhu, Peng Miao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Phosphorylation of DNA is a critical event for normal cell processes such as DNA replication, DNA repair and DNA recombination. It is important to develop accurate and convenient approach for the detection of kinase and inhibition. In this work, we have described a novel sensing strategy for T4 polynucleotide kinase. A single-stranded DNA probe is firstly immobilized on the surface of the electrode. After phosphorylated by target kinase, it could be ligated with amino group labeled DNA probe by certain hybridization. Denaturation process is then proceeded to release unligated DNA probes, which may help reduce the background signal. The remained amino groups could be used to adsorb silver nanoparticles (AgNPs) as electrochemical species for the quantification of T4 polynucleotide kinase. This biosensor shows high sensitivity and selectivity. It may also be used for the screening kinase inhibitors. Therefore, it shows great potential utility in biological process investigation, drug discovery and clinical diagnosis.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309122-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 2 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Xiangheng Niu, Kun Ye, Linjie Wang, Yuehe Lin, Dan Du〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Alkaline phosphatase (ALP) is a natural enzyme that is able to catalyze the dephosphorylation of phosphate esters. It participates in a great number of biological processes ranging from various metabolisms to signal transduction and cellular regulation. Since the abnormality of ALP activity in body is closely associated with many diseases, it has become an important biomarker for clinical diagnosis and treatment. Besides, it is often utilized in enzyme-linked immunosorbent assays. Given these demands, in the last few years considerable interest has been focused on exploring new materials and methods for ALP activity detection. In this review, we first made a clear classification on the principles that could be used for ALP activity determination. After that, emerging colorimetric and fluorescent strategies designed on the basis of these principles were systematically summarized. Finally, some perspectives on ALP activity analysis were discussed, hoping to inspire future efforts in the field.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309067-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 2 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Caoling Li, Junxing Hao, Kangbing Wu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The simultaneous determination of xanthine (XA) and hypoxanthine (HXA) has been proved to be a feasible approach for the assessment of fish freshness. In this study, copper(II) nitrate and 1,3,5-benzenetricarboxylic acid (H〈sub〉3〈/sub〉BTC) were used as precursors to prepare various Cu-BTC frameworks with the addition of various amounts of triethylamine at room temperature. The characterization of X-ray diffraction, Fourier-transform infrared spectroscopy and Raman spectroscopy testified that the obtained materials are Cu-BTC frameworks. However, the amount of triethylamine had significant effects on the morphology, active response area and electron transfer ability of Cu-BTC frameworks. The oxidation behavior of XA and HXA demonstrated that the prepared Cu-BTC frameworks exhibited higher sensing activity, with greatly-enhanced oxidation signals. More importantly, the amount of triethylamine obviously affected the accumulation capacity and signal enhancement ability of Cu-BTCs toward XA and HXA, as confirmed from double potential step chronocoulometry. Based on the triethylamine-tuned signal amplification strategy of Cu-BTC frameworks, a highly-sensitive and simple electrochemical sensing system was developed for the assessment of fish freshness by simultaneous detection of XA and HXA. The developed sensing method was used in practical samples, and the results were validated by high-performance liquid chromatography.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S000326701930902X-fx1.jpg" width="269" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 7 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Chia-Wen Lien, Po-Hsiung Yu, Huan-Tsung Chang, Pang-Hung Hsu, Tsunghsueh Wu, Yang-Wei Lin, Chih-Ching Huang, Jui-Yang Lai〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, we report the synthesis and application of enzyme-like DNA-copper oxide/platinum nanoparticles for the separate quantification of inorganic and organomercury species in various real samples. We synthesized a series of poly(thymine) (T〈sub〉60〈/sub〉)–copper oxide/metal nanocomposites (T〈sub〉60〈/sub〉–Cu〈sub〉〈em〉x〈/em〉〈/sub〉O/M NCs; M = Au, Ag or Pt) that exhibited enzyme-like activities [oxidase (OX), peroxidase (POX), and catalase (CAT)]. The enzyme-like activities are tunable due to the incorporation of various metals into the NCs. Among a series of synthesized Cu〈sub〉〈em〉x〈/em〉〈/sub〉O/M NCs, T〈sub〉60〈/sub〉–copper oxide-platinum nanocomposites (T〈sub〉60〈/sub〉–Cu〈sub〉〈em〉x〈/em〉〈/sub〉O/Pt NCs) exhibited the highest OX-like activity via the O〈sub〉2〈/sub〉-mediated oxidation of substrates, such as Amplex Red (AR), 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), 〈em〉o〈/em〉-phenylenediamine (OPD), and 3,3′,5,5′-tetramethylbenzidine (TMB), to form fluorescent or colored products. Interestingly, inorganic mercury ions (Hg〈sup〉2+〈/sup〉) and organomercury species, such as methylmercury (MeHg〈sup〉+〈/sup〉), ethylmercury (EtHg〈sup〉+〈/sup〉), and phenylmercury (PhHg〈sup〉+〈/sup〉), significantly inhibited the OX-like activity of T〈sub〉60〈/sub〉–Cu〈sub〉〈em〉x〈/em〉〈/sub〉O/Pt NCs. For the selective detection of mercury species, we used ABTS in the T〈sub〉60〈/sub〉–Cu〈sub〉〈em〉x〈/em〉〈/sub〉O/Pt NCs system, and the ABTS/T〈sub〉60〈/sub〉–Cu〈sub〉〈em〉x〈/em〉〈/sub〉O/Pt NCs-based assay allowed for the detection of mercury ions at nanomolar concentrations based on the decrease in the catalytic activity caused by the mercury ions. To separately quantify the inorganic and organomercury species in a sample, we employed selenium nanoparticles (Se NPs) as a masking agent, as they preferentially bind with inorganic mercury species. The ABTS/T〈sub〉60〈/sub〉–Cu〈sub〉〈em〉x〈/em〉〈/sub〉O/Pt NCs-based assay with the masking agent of Se NPs further provided specificity for the detection of organomercury species in environmental water samples (tap water, river water, and seawater) and fish muscle samples (dogfish muscle DORM-II).〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309225-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 7 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Ying Li, Chuanfeng Yu, Caisheng Zhao, Chunnian Ren, Xiaoru Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel method of catalytic hairpin assembly (CHA) induced dual signal enhancement is developed for rapid detection of miRNA based on fluorescence light-up silver nanocluster (Ag NC). By the hybridization of a hairpin DNA and a single-stranded DNA, a unique probe is firstly designed. In the terminals of this probe, DNA-Ag NCs can be formed and display very weak fluorescence. In the presence of the target miRNA, the reaction of CHA can be triggered, forming two kinds of double-stranded complexes, in which the terminal DNA-Ag NCs are in close proximity to G-rich overhangs and the fluorescent signal can be dramatically enhanced. Compared with many other enzyme-based amplification strategies, this one exhibits distinct advantages of simplicity in experimental operation and a rapid detection process (within 1 h). Moreover, this assay exhibits an excellent selectivity and is successfully applied in the detection of miRNAs in complex biological media, which confirms the reliability and practicality of this protocol.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉A novel method of catalytic hairpin assembly (CHA) induced dual signal enhancement is developed, which has been used for rapid detection of miRNA based on fluorescence light-up silver nanocluster.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309201-fx1.jpg" width="250" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 7 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Keisean A.J.M. Stevenson, Leonid M. Blumberg, James J. Harynuk〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Comprehensive two-dimensional gas chromatography (GC × GC) provides enhanced separation power over its one-dimensional counterpart – gas chromatography (GC). This enhancement is achieved by the inclusion of a secondary column, the choice of which is a major determinant on the quality of the ultimate separation. When developing and optimizing a new GC × GC method, the choices of stationary phase chemistries, geometries and configurations (which phase serves in which dimension) are of fundamental importance, and must often be addressed even before the manipulation of instrumental conditions. These choices are often made using educated guesses, literature searches, or trial and error. Thermodynamic models of GC separations; however, provide a fast and easy means of acquiring information for guiding these choices. By using characteristic thermodynamic parameters (characteristic temperatures, 〈em〉T〈/em〉〈sub〉〈em〉char〈/em〉〈/sub〉, and characteristic thermal constants, 〈em〉θ〈/em〉〈sub〉〈em〉char〈/em〉〈/sub〉), we demonstrate the generation of maps that can inform the choices of column chemistries, phase ratios and configurations for GC × GC separations.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309249-fx1.jpg" width="363" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 7 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Naader Alizadeh, Alireza Akbarinejad, Saman Hosseinkhani, Fatemeh Rabbani〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Conjugated polymers for bioimaging and sensing chemical/biological reagents have received much attention owing to their outstanding photophysical properties. However, most conventional synthetic strategies result in aggregates of conjugated polymers with limited solubility in most common organic and aqueous solvents. Therefore, advancement in molecular design and synthetic pathways is required to tune the optical and solubility properties of the resulting conjugated polymers. Herein, a simple, general, and effective approach for the synthesis of water-soluble polypyrrole (PPy) is reported based on the chemical polymerization in the presence of a homologue series of dicarboxylic acids with different chain lengths as multifunctional dopant molecules, possessing two carboxylic acid groups which serve as both dopants and stabilizing agents. The role of dopant chain length on the emission properties of resulting water-soluble polymers has been investigated. Among the synthesized water-soluble polymers, succinic acid-stabilized polymer (PPy-Suc) showed the highest emission wavelength (λ〈sub〉em〈/sub〉 = 453 nm), high quantum yield (12.87), very good photostability and low cytotoxicity, suggesting its applicability in bioimaging and sensing applications. As a proof of concept, the PPy-Suc polymer was successfully utilized in cellular imaging. Moreover, a novel fluorescence iodide sensor with two linear ranges of 0.012–0.200 and 0.200–8.825 μM and a low detection limit of 9 nM was developed based on the prepared PPy-Suc polymer. The superior properties of the synthesized water-soluble polymers confirm the potential applicability of developed method as a general, facile and effective synthesis approach in preparation of water-soluble conjugated polymers with several potential applications.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309213-fx1.jpg" width="296" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 7 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Cun Wang, Min Chen, Jingling Wu, Fangjing Mo, Yingzi Fu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Novel lanthanum ion-doped cadmium sulfide quantum dots (CdS:La QDs) were synthesized and characterized by transmission electron microscopy (TEM) and photoluminescence (PL). Based on CdS:La QDs as the electrochemiluminescence (ECL) luminophores, a distance-dependent ECL intensity enhanced or quenched system between CdS:La QDs and gold nanoparticles (Au NPs) was designed. Firstly, ssDNA 1 was linked to the CdS:La QDs modified glassy carbon electrode via amide bond. Then the prepared Au NP–ssDNA 2 conjugates were used to hybridize with ssDNA 1, the surface plasmon resonances (SPR) of Au NPs enhanced ECL intensity (signal on) while Au NPs and CdS:La QDs were separated at a certain distance. Secondly, In the presence of Hg〈sup〉2+〈/sup〉, the oligonucleotide conformation changed from linear chain to hairpin due to the thymine–Hg〈sup〉2+〈/sup〉–thymine (T–Hg〈sup〉2+〈/sup〉–T) base pairs. ECL quenching (signal off) achieved lie in resonance energy transfer (RET) between the CdS:La QDs and the proximal Au NPs at a close distance. Finally, after being incubated with TB, a strong and stable TB–aptamer complex was generated, which led to the release of Au NP–ssDNA 2 conjugates. The ECL signal of the CdS:La QDs was ultimately recovered (signal on again). The “on–off–on” approach was used to detect Hg〈sup〉2+〈/sup〉 and TB, sensitively and respectively. The line ranges were 1.00 × 10〈sup〉−12〈/sup〉 –1.00 × 10〈sup〉−5〈/sup〉 mol L〈sup〉−1〈/sup〉 and 1.00 × 10〈sup〉−16〈/sup〉 –1.00 × 10〈sup〉−6〈/sup〉 mol L〈sup〉−1〈/sup〉, respectively. The low limits of detection (S/N = 3) were at 3.00 × 10〈sup〉−13〈/sup〉 mol L〈sup〉−1〈/sup〉 and 3.00 × 10〈sup〉−17〈/sup〉 mol L〈sup〉−1〈/sup〉. Moreover, the ECL sensor exhibited high selectivity and good stability, and was successfully applied to the detection of TB in real sample.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309250-fx1.jpg" width="247" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 6 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Monika Śmiełowska, Bożena Zabiegała〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉In the present study a novel analytical procedure for the determination of polybrominated diphenyl ethers in dust samples was developed.〈/p〉 〈p〉The main aim of the research was the selection of the optimum conditions of the matrix solid-phase dispersion before the final determination of polybrominated diphenyl ethers in dust samples. In order to assess the best usefulness of this technique, a favourable ratio of sample amount to the mass of dispersing sorbent, as well as the type of this sorbent used has been tested. The type of sorbent responsible for additional purification (clean-up sorbent) of the extract during matrix solid-phase dispersion was also selected. Gas chromatography coupled with mass spectrometry will be used at the final determination step.〈/p〉 〈p〉Preliminary results indicate that the use of matrix solid-phase dispersion can be a promising alternative to other time-consuming and multi-stage analytical procedures. The proposed method provided satisfactory recoveries (76–119%) and limits of detection: 2.1–4.4 pg μL〈sup〉−1〈/sup〉 for tri-heptaBDE in linear range of 5–100 pg μL〈sup〉−1〈/sup〉; 480 pg μL〈sup〉−1〈/sup〉 for decaBDE in linear range of 500–2000 pg μL〈sup〉−1〈/sup〉 from only 0.05 g of a dust sample. Finally, the method was applied to study the content of selected polybrominated diphenyl ethers in real dust samples. Some polybrominated diphenyl ether congeners reached up to (16.3 ± 3.0)·10〈sup〉2〈/sup〉 ng g〈sup〉−1〈/sup〉.〈/p〉 〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309134-fx1.jpg" width="449" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 7 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Milan Boublík, Martina Riesová, Vlastimil Hruška, Jana Šteflová〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Within the frame of the dynamic pH junction preconcentration technique in capillary electrophoresis, we introduce a novel approach based on the use of the pH boundary of a system zone for the preconcentration of general, multivalent, weak analytes in a system of binary, uni-univalent, background electrolytes (BGE). For such purpose, in addition to presenting a comprehensive flowchart for the development of a method for BGE preconcentration, we showed several model cases using acidic, basic and ampholytic analytes. Furthermore, we combined the flowchart with calculations in electrophoretic software PeakMaster to determine all necessary information such as analyte mobility, system zones and the amplitude of the pH boundary of a system zone as a function of the sample matrix. For an even more detailed understanding of the process, we also investigated changes in the pH boundary through computer simulations with Simul 5, providing an in-depth characterization of all model analytes according to the steps of the flowchart and to PeakMaster calculations for experimental verification of the final BGE preconcentration.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S000326701930916X-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 6 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Valentina Marassi, Francesca Beretti, Barbara Roda, Andrea Alessandrini, Paolo Facci, Tullia Maraldi, Andrea Zattoni, Pierluigi Reschiglian, Marinella Portolani〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Protein misfolding and aggregation are the common mechanisms in a variety of aggregation-dependent diseases. The compromised proteins often assemble into toxic, accumulating amyloid-like structures of various lengths and their toxicity can also be transferred both in 〈em〉vivo〈/em〉 and in 〈em〉vitro〈/em〉 a prion-like behavior.〈/p〉 〈p〉The characterization of protein interactions, degradation and conformational dynamics in biological systems still represents an analytical challenge in the prion-like protein comprehension.〈/p〉 〈p〉In our work, we investigated the nature of a transferable cytotoxic agent, presumably a misfolded protein, through the coupling of a multi-detector, non-destructive separation platform based on hollow-fiber flow field-flow fractionation with imaging and downstream in vitro tests.〈/p〉 〈p〉After purification with ion exchange chromatography, the transferable cytotoxic agentwas analyzed with Atomic Force Microscopy and statistical analysis, showing that the concentration of protein dimers and low n-oligomer forms was higher in the cytotoxic sample than in the control preparation. To assess whether the presence of these species was the actual toxic and/or self-propagating factor, we employed HF5 fractionation, with UV and Multi-Angle Light Scattering detection, to define proteins molar mass distribution and abundance, and fractionate the sample into size-homogeneous fractions. These fractions were then tested individually in 〈em〉vitro〈/em〉 to investigate the direct correlation with cytotoxicity. Only the later-eluted fraction, which contains high-molar mass aggregates, proved to be toxic onto cell cultures. Moreover, it was observed that the selective transfer of toxicity also occurs for one lower-mass fraction, suggesting that two different mechanisms, acute and later induced toxicity, are in place. These results strongly encourage the efficacy of this platform to enable the identification of protein toxicants.〈/p〉 〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309158-fx1.jpg" width="350" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 17 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Chi Li, Yuanyuan Zhang, Ting Zeng, Xinyue Chen, Wenqian Wang, Qijin Wan, Nianjun Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To explore suitable sensing materials for sensitive and selective detection of phenolic pollutants, CeO〈sub〉2〈/sub〉 nanocubes, nanopolyhedras, and nanorods were synthesized by a hydrothermal method. These CeO〈sub〉2〈/sub〉 nanomaterials were further loaded on the support of graphene nanoplatelets. As-synthesized nanomaterials and nanocomposites were characterized using transmission electron microscopy, X-ray diffraction and Raman spectroscopy as well as electrochemical techniques including cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse voltammetry. The nanocomposite of graphene nanoplatelets with CeO〈sub〉2〈/sub〉 nanorods shows the highest electrochemical activity towards soluble species. Highly sensitive and selective determination of tetrabromobisphenol A, catechol, diethylstilbestrol, and nonylphenol was thus achieved at this nanocomposite based electrode. Their limits of detection were as low as 1.8, 42, 1.5 and 2.7 nM, respectively. Such an electrochemical sensor is thus promising for simple, fast and sensitive electrochemical determining of trace-leveled phenolic pollutants in water samples.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309651-fx1.jpg" width="456" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 17 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Jinlong Li, Kai Hu, Yongchen Zhang, Zhaoli Zhang, Yongfeng Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Estrogen receptors (ERs) play a major role in the signaling pathways and participate in regulating and maintaining the basic activities of life. The abnormal expression of ERs has a significant effect on tumorigenesis. Herein, we propose an electrochemical method for detecting ERs based on the formation of DNA Y-Junction with a 3′-blunt end. The DNA Y-junction was designed to have one of its arms bound to an ER. When an ER was bound to the junction, which was immobilized on the electrode surface, it protected the DNA Y-junction from Exo III-catalyzed digestion. DNA Y-Junction also contained G-quadruplex rich duplex, which generated electrochemical signals when hemin was added to the electrode, resulting in the quantitative detection of ERs. The detection range of the ER using this method was 0.1–200 nM with a detection limit of 0.034 nM. Since this assay can be employed to detect ERs in tumor cells, it may be useful in tumor diagnosis in the future.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309699-fx1.jpg" width="378" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 17 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Ali Azizi, Fereshteh Shahhoseini, Ali Modir-Rousta, Christina S. Bottaro〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Sample preparation has remained a bottleneck in analysis of biological and environmental samples. Thus, microextraction techniques to reduce time, cost, labor, and environmental impacts as compared to traditional solid phase or liquid-liquid extractions are appealing. In this work, a high throughput extraction method coupled with a novel desorption technique has been developed for the analysis of eight regulated PAHs in water. The targeted analytes were extracted by thin film microextraction (TFME) using single-use sorbents. The enriched analytes on thin films were directly introduced into a gas chromatography with a flame ionization detector (GC-FID) through solvothermal headspace desorption (ST-HD). The desorption of analytes was accelerated by adding a small volume of solvent into the headspace vial. The parameters that influence desorption, such as type and volume of solvent, oven temperature, and desorption time, were studied. As well, the key parameters (stirring rate, extraction time, and salt content) for TFME of PAHs from water were assessed and optimized. Reusability and durability of the film and background noise due to polymer decomposition were also assessed. The method was validated using standards in 3.5% aqueous NaCl. The limits of detection (LODs) were between 0.2 and 2.0 ng mL〈sup〉−1〈/sup〉, with linear ranges of 0.4–200.0 ng mL〈sup〉−1〈/sup〉 with R〈sup〉2〈/sup〉 〉 0.99, and satisfactory accuracy and repeatability at three concentrations (low, mid, and high) within the linear range of the calibration curves. The calibration curves were also assessed for suitability as a matched matrix in the analysis of PAHs in a seawater sample. The technique was also applied for determination of PAHs in a produced water sample without the need for pretreatment and filtration of the sample. Although the complexity of produced water required the use of standard addition, we demonstrated that this approach is a useful tool for the analysis of complicated environmental samples.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309638-fx1.jpg" width="226" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 17 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Tianze Li, Shuang E, Jianhua Wang, Xuwei Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Carbon dots (CDs) were prepared by a solvent-involved molecular fusion strategy using o-phenylenediamine (OPD) as the carbon source and formamide as the reaction solvent. The CDs possessed not only the functional groups inherited from the carbon source and the reaction solvent, but also numerous C=N groups in the structure, resulting from the Schiff base reaction between –NH〈sub〉2〈/sub〉 of OPD and C=O of formamide. These functional groups endowed the final CDs with a favorable soft-base property, leading to the high tolerance level toward hard-acid type metal ions and prominent detection selectivity toward Ag〈sup〉+〈/sup〉. Moreover, the obtained CDs displayed outstanding biocompatibility and low cytotoxicity, and demonstrated potential as an effective photoluminescence probe for intercellular Ag〈sup〉+〈/sup〉 and Cys imaging, preventing the interference of autofluorescence from living tissues. This study focused on the solvent-involved molecular fusion strategy could provide new insights into the design of novel carbon-based nanostructures and optimization of the structure-property relationship of CDs.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉CDs prepared via a solvent-involved molecular fusion strategy using formamide as reaction solvent exhibits prominent detection selectivity toward Ag〈sup〉+〈/sup〉.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309687-fx1.jpg" width="352" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 13 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Jiaxin Zheng, Xiaolun Peng, Yijia Wang, Ting Bao, Wei Wen, Xiuhua Zhang, Shengfu Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The development of some sensitive methods for MUC1 is critical for preclinical diagnosis of tumors. In this experiment, we built a triple-amplified electrochemical aptasensor to achieve sensitive detection of MUC1, which was based on exonuclease III (Exo III)-assisted with strand displacement reaction and enzyme catalytic strategy. Firstly, with the help of Exo III, MUC1 and aptamer could be recycled during the cycle I, the single stranded DNA-1 (S-1) was produced during the process and was introduced to the hybride reaction on the electrode. Secondly, during the cycle II, strand displacement reaction was triggered on the electrode with the adding of hairpin DNA-2 (H-2). Thirdly, after the gold nanoparticles (AuNPs)-DNA-enzyme conjugates hybrided with the H-2 on the electrode, the AuNPs-DNA-enzyme conjugates could act as signal probe to produce electrochemical catalytic signal. We used the fabricated triple-amplified electrochemical aptasensor that could detect MUC1 from 0.1 pg mL〈sup〉−1〈/sup〉 to 10 ng mL〈sup〉−1〈/sup〉 with the detection limit of 0.04 pg mL〈sup〉−1〈/sup〉 under the optimized experimental conditions. The constructed triple-amplified electrochemical aptasensor could be applied in real samples determination. Besides, the strategy can be applied to detect other proteins for health monitoring.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309468-fx1.jpg" width="245" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 9 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Mohamed Adel Ahmed, Bren Mark B. Felisilda, Joselito P. Quirino〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This review critically discusses the developments on open-tubular liquid chromatography (OT-LC) and open-tubular capillary electrochromatography (OT-CEC) during 2014–2018. An appropriate Scopus search revealed 5 reviews, 4 theoretical papers on open-tubular format chromatography, 29 OT-LC articles, 68 OT-CEC articles and 4 OT-LC/OT-CEC articles, indicating a sustained interest in these areas. The open-tubular format typically uses a capillary column with inner walls that are coated with an ample layer or coating of solid stationary phase material. The ratio between the capillary internal diameter and coating thickness (CID/CT) is ideally ≤ 100 for appropriate chromatographic retention. We, therefore, approximated the CID/CT ratios and found that 22 OT-LC papers have CID/CT ratios ≤100. The other 7 OT-LC papers have CID/CT ratio 〉100 but have clearly demonstrated chromatographic retention. These 29 papers utilised reversed phase or ion exchange mechanisms using known or innovative solid stationary phase materials (〈em〉e.g.〈/em〉 metal organic frameworks), stationary pseudophases from ionic surfactants or porous supports. On the other hand, we found that 68 OT-CEC papers, 7 OT-LC papers and 4 OT-LC & OT-CEC papers have CID/CT ratios 〉100. Notably, 44 papers (42 OT-CEC and 2 OT-LC & OT-CEC) did not report the retention factor and/or effective electrophoretic mobility of analytes. Considering all covered papers, the most popular activity was on the development of new chromatographic materials as coatings. However, we encourage OT-CEC researchers to not only characterise changes in the electroosmotic flow but also verify the interaction of the analytes with the coating. In addition, the articles reported were largely driven by stationary phase or support development and not by practical applications.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309432-fx1.jpg" width="263" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 2 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Xiao Hu, Cerasela Zoica Dinu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Acetylcholinesterase (AChE), an efficient biocatalyst known to hydrolyze the neurotransmitter acetylcholine, could be inactivated in the presence of insecticides, nerve agents or other drug inhibitors to thus result in disrupted neurotransmission. Improvement in the peripheral cholinergic function, as well as overall cognition and neuronal functions of an exposed system could be achieved if the mechanisms of inhibitions are deactivated in a controlled fashion and with rapid response time. Herein, we proposed to develop a simple AChE biosensor capable to realize the rapid detection of neurotoxins. Our approach uses a nanoporous gold film (NPGF) and reduced graphene oxide-tin dioxide nanoparticle (RGO-SnO〈sub〉2〈/sub〉) nanocomposite to define the highly active electrode interface where the electrochemical monitoring of the interaction between AChE and its target molecule, fasciculin, could take place. Our results demonstrate that the established biosensor had the ability to monitor fasciculin concentrations at the ultra-low limit of detection of 8 pM, an inhibition rate of 8% and within only 30min of electrochemical exposure. Our study provides a convenient technology for the rapid and ultrasensitive detection of neurotoxins and has the potential for large applicability to other drugs or toxins screening.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309055-fx1.jpg" width="371" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 2 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Mahmoud Tabibpour, Yadollah Yamini, Hamid Ahmadi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉For the first time, a rapid, efficient, simple, and inexpensive approach for solid phase microextraction on a screw (MES) was developed. MES is a miniaturized form of solid-phase extraction without any backpressure. In this system, analytes were adsorbed on the surface of micro channels of a screw that was coated by polypyrrole (PPy). Based on this procedure, the analytes are adsorbed on the solid phase and then eluted by a desorption solvent. The MES method followed by gas chromatography–mass spectrometry (MES-GC-MS) was applied for the rapid extraction and determination of six polycyclic aromatic hydrocarbons (PAHs) (as model analytes) in well water samples. Several parameters affecting the extraction procedure, including the sampling flow rate, the number of the loading/desorption cycles of the sample, and the volume of the desorption solvent, were evaluated and optimized. Under optimum conditions, the detection limits for the PAHs varied between 0.5 and 1 μg L〈sup〉−1〈/sup〉 and linear ranges varied between 2 and 600 μg L〈sup〉−1〈/sup〉. The results showed good correlation coefficients (R 〉 0.99) for all of the analytes in the studied calibration range. The relative recovery (RR%) of the desired MES–GC–MS method for the studied PAHs was between 83.0 and 104.0% and the interday and intraday precision (n = 5 days), expressed as relative standard deviation (RSD %), were between 3.9-6.2% and 6.2–8.9%, respectively. To evaluate the matrix effect, the developed method was also applied for preconcentration and determination of the selected PAHs in real water samples, and good results were obtained.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019309079-fx1.jpg" width="325" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 21 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1049〈/p〉 〈p〉Author(s): Somaiyeh Khodadadi Karimvand, Marcel Maeder, Hamid Abdollahi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉In many equilibrium systems, it is customary to use a simplified, apparent equilibrium reaction instead of the complete reaction model. The resulting apparent equilibrium constants are altered or controlled by changes of the chemical system, usually modifying the total concentration of auxiliary reagents, but the variation of other parameters such the intensity of light in photo-controlled reactions, types and concentration of solvents or composition of mixed solvents, the ionic strength of the chemical media, etc. is also possible. The main goal of this work is to propose a chemical equilibrium modelling based strategy to control the conditions governing equilibrium systems in order to tune the apparent constants. Indeed, by extracting the analytic relationship between the parameters of the complete model and apparent model, the magnitude of the apparent constant(s) can be predicted.〈/p〉 〈p〉At first, a basic strategy for calculating the tunable range of apparent constants of chemical equilibria is proposed. Next, three case studies for tuning the apparent constants are investigated in detail: inclusion complexes with cyclodextrin, aqueous micellar solutions for investigating the solvent effects and the boric acid/Mannitol system that allows the tuning of the apparent protonation constant. In all examples tuning the apparent constant is possible by regulating the chemical composition.〈/p〉 〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018312777-fx1.jpg" width="355" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 7 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1050〈/p〉 〈p〉Author(s): Hai Wang, Youyi Ni, Jian Zheng, Zhaoya Huang, Detao Xiao, Tatsuo Aono〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Two fusion methods were established for rapid determination of Pu in soil and sediment samples. The methods consisted of NH〈sub〉4〈/sub〉HSO〈sub〉4〈/sub〉 or NH〈sub〉4〈/sub〉HF〈sub〉2〈/sub〉 fusion procedures incorporated with procedures for CaF〈sub〉2〈/sub〉/LaF〈sub〉3〈/sub〉 co-precipitation, extraction chromatography and SF-ICP-MS measurement. The fusion procedures were done on a portable hot plate instead of in a cumbersome muffle furnace and took only 15 min heating-up time from room temperature to 250 °C and 15 min fusion time at 250 °C. Chemical recoveries of Pu after completing the NH〈sub〉4〈/sub〉HSO〈sub〉4〈/sub〉 and NH〈sub〉4〈/sub〉HF〈sub〉2〈/sub〉 fusion methods for 0.5–1 g sample were approximately 70% and more than 90%, respectively, and decreased with the increase of sample weight from 0.5 g to 5 g. Sediment samples were pre-ignited at different temperatures ranging from 450 °C to 1000 °C to form refractory fractions of Pu, with which the dissolution rates of Pu by the NH〈sub〉4〈/sub〉HSO〈sub〉4〈/sub〉 and NH〈sub〉4〈/sub〉HF〈sub〉2〈/sub〉 fusion were investigated. With the increase of pre-ignition temperature of the sediment samples, the dissolution rates of Pu from the samples prepared by NH〈sub〉4〈/sub〉HSO〈sub〉4〈/sub〉 fusion declined dramatically from near 100% for 450 °C to 8% for 1000 °C. In contrast, the NH〈sub〉4〈/sub〉HF〈sub〉2〈/sub〉 fusion was capable of completely releasing Pu from samples that were pre-ignited at temperatures over 450 °C to 1000 °C, which was comparable to releases obtained by the hazardous and time-consuming HNO〈sub〉3〈/sub〉-HF digestion, and was superior to the conventional HNO〈sub〉3〈/sub〉 digestion. Additionally, because HF is not used in any procedure of the NH〈sub〉4〈/sub〉HF〈sub〉2〈/sub〉 fusion, a safer and greener alternative to NH〈sub〉4〈/sub〉HSO〈sub〉4〈/sub〉 fusion and HNO〈sub〉3〈/sub〉-HF digestion is realized for rapid Pu determination in environmental samples for nuclear emergency response and application in environmental studies.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018313072-fx1.jpg" width="426" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 7 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1050〈/p〉 〈p〉Author(s): Wen-Fang Du, Jian-Hui Ge, Jun-Jie Li, Li-Juan Tang, Ru-Qin Yu, Jian-Hui Jiang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Loop-mediated isothermal amplification (LAMP) is a useful platform for nucleic acids detection in point-of-care (POC) situations, and development of single-step, close-tube LAMP reactions for specific detection of single nucleotide mutations (SNMs) remains a challenge. We develop a novel primer-activatable LAMP (PA-LAMP) strategy that enables highly specific and sensitive SNM detection using single-step, close-tube reactions. This strategy designs a terminal-blocked inner primer with a ribonucleotide insertion, which is cleaved and activated specifically to perfectly matched targets by ribonuclease (RNase) H2, to realize efficient amplification of mutant genes. It has shown dynamic responses of mutant target in a linear range from 220 aM to 22 pM with a lowest detectable concentration of 22 aM. It also demonstrates very high specificity in identifying the mutant in a large excess of the wild-type with a discrimination ratio as high as ∼10,000. It has been successfully applied to mutation detection of genomic DNA in tumor cells. The PA-LAMP strategy provides a useful, portable and affordable POC platform for highly sensitive and specific detection of genetic mutations in clinical applications.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018313242-fx1.jpg" width="266" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 4 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1052〈/p〉 〈p〉Author(s): Muhammed Ariful Islam, Parvez Mahbub, Pavel N. Nesterenko, Brett Paull, Mirek Macka〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Electrochemical (EC) detection techniques in flow-based analytical systems such as flow injection analysis (FIA), capillary electrophoresis (CE), and liquid chromatography (LC) have attracted continuous interest over the last three decades, leading to significant advances in EC detection of a wide range of analytes in the liquid phase. In this context, the unique advantages of pulsed amperometric detection (PAD) in terms of high sensitivity and selectivity, and electrode cleaning through the application of pulsed potential for noble metal electrodes (e.g. Au, Pt), have established PAD as an important detection technique for a variety of electrochemically active compounds. PAD is especially valuable for analytes not detectable by ultraviolet (UV) photometric detection, such as organic aliphatic compounds and carbohydrates, especially when used with miniaturised capillary and chip-based separation methods. These applications have been accomplished through advances in PAD potential waveform design, as well as through the incorporation of nanomaterials (NMs) employed as microelectrodes in PAD. PAD allows on-line pulsed potential cleaning and coupling with capillary or standard separation techniques. The NMs are largely employed in microelectrodes to speed up mass and electron transfer between electrode surfaces and to perform as reactants in EC analysis. These advances in PAD have improved the sensitive and selective EC detection of analytes, especially in biological samples with complex sample matrices, and detection of electro-inactive compounds such as aliphatic organic compounds (i.e., formic acid, acetic acid, maleic acids, and β-cyclodextrin complexes). This review addresses the fundamentals of PAD, the role of pulsed sequences in AD, the utilisation of different EC detectors for PAD, technological advancements in PAD waveforms, utilisation of microelectrodes in PAD techniques, advances in the use of NMs in PAD, the applications of PAD, and prospects for EC detection, with emphasis on PAD in flow-based systems.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018313084-fx1.jpg" width="385" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 7 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1050〈/p〉 〈p〉Author(s): Chia-Wei Hsu, Yi-Ting Chen, Ya-Ju Hsieh, Kai-Ping Chang, Pei-Chun Hsueh, Ting-Wen Chen, Jau-Song Yu, Yu-Sun Chang, Liang Li, Chih-Ching Wu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Oral cavity squamous cell carcinoma (OSCC), the most common malignancy of the oral cavity, is associated with poor prognosis and high mortality worldwide. Moreover, knowledge of the metabolic alterations that occur in OSCC is still limited. In the present study, we used a quantitative metabolomic approach with chemical isotope labeling (CIL) to analyze alterations in the metabolite levels in paired cancerous (T) and adjacent noncancerous (AN) tissues from 31 OSCC patients. Using volcano plot and orthogonal projections to latent structure-discriminant analysis (OPLS-DA), we uncovered 99 dysregulated metabolites in OSCC and verified the identities of seven metabolites via comparison with authenticated standards. From these seven metabolites, we constructed a 3-marker panel, consisting of putrescine, glycyl-leucine, and phenylalanine, using a support vector machine (SVM) model that can discriminate T from AN with high sensitivity and specificity based on receiver operator characteristic (ROC) analysis. Furthermore, by integrating the metabolomics profiles with transcriptomics data obtained from the same sample set, we revealed the dysregulation of the polyamine pathway in OSCC. Our findings provide insights into the metabolic perturbations present in OSCC and have uncovered potential metabolic biomarkers and therapeutic targets for use in the treatment of OSCC.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018313266-fx1.jpg" width="207" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 7 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1050〈/p〉 〈p〉Author(s): Virginia Moreno, Mohammed Zougagh, Ángel Ríos〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Analytical nanometrology is a present challenge in today's analytical science, particularly from a practical point of view and when it is addressed to routine/control laboratories. In this way, a screening-confirmation approach is described for the characterization and distinction between titanium dioxide nano/micro-particles in sugary food samples. The first step involves the confirmation of the presence of TiO〈sub〉2〈/sub〉 in the sample (used as additive E171 in sugary samples), using a portable Raman spectrometer, in which the crystalline structure of TiO〈sub〉2〈/sub〉 (anatase or rutile) in the positive samples can be also obtained in this step. Then, the second step was only applied to positive samples, and it involves the use of Capillary Electrophoresis (CE), which allows to distinguish between TiO〈sub〉2〈/sub〉-nanoparticles (〈100 nm) from TiO〈sub〉2〈/sub〉-microparticles (〉100 nm). Additionally, nanoparticles (TiO〈sub〉2〈/sub〉 anatase (5 nm diameter) and TiO〈sub〉2〈/sub〉 rutile (60 nm diameter) and rutile microparticles (0.1–0.2 μm diameter) can be electrophoretically separated. The general procedure is simple, fast, and low cost, providing a valuable analytical tool in the field of food safety and control, thus contributing to the development of the analytical nanometrology.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018313096-fx1.jpg" width="266" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 27 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Jun Yao, Min Chen, Nannan Li, Chaohui Liu, Mei Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As an ideal alternative to bisphenol A (BPA), bisphenol S (BPS) has similar biotoxicity, teratogenicity, carcinogenicity and mutagenicity as BPA. Nevertheless, to date, a fast, sensitive and portable method for meeting on-site measurement of BPS had not been established. Hence, it was particularly urged to develop a fast and highly sensitive method for tracing BPS. Currently, a novel molecularly imprinted polymer (MIP) electrochemical sensor had been successfully fabricated for the detection of BPS, wherein the composite of three-doped carbon quantum dots (B,N,F-CQDs) and silver nanoparticles (AgNPs) were utilized as an electron conducting layer, and MIP was applied as recognition element of target molecules. The step-by-step fabrication process and the adsorption capacity of the modified electrode were evaluated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronocoulometry (CC). The results indicated that the synergy between B,N,F-CQDs and AgNPs dramatically improved the sensitivity of the electrode and achieved the amplification of the electrical signal. Meanwhile, the electrochemical activities of BPS were explored by CV and differential pulse voltammetry (DPV). And, the various parameters relating to the electrochemical kinetic properties of BPS were calculated. To the best of our knowledge, this was rarely reported in peer journals. The MIP remarkably improved the selectivity of the sensor owing to the specific recognition of the imprinted cavities. The linear response range of the new sensor was 1 × 10〈sup〉−8〈/sup〉 M to 5 × 10〈sup〉−5〈/sup〉 M with a detection limit of 1.12 × 10〈sup〉−8〈/sup〉 M and the electrode designed in this paper could meet the requirement of trace-level measurement of BPS in biological and environmental samples. Additionally, the sensor was used to determine BPS in plastic products with good anti-interference and acceptable recovery.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019303678-fx1.jpg" width="235" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 27 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Huaping Peng, Pan Liu, Weihua Wu, Wei Chen, Xiangying Meng, Xinhua Lin, Ailin Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This report outlines an ultrasensitive electrochemiluminescence (ECL) sensing platform based on water-soluble tungsten oxide quantum dots (WO〈sub〉x〈/sub〉 QDs) for the detection of dopamine (DA) released from P12 cells. The WO〈sub〉x〈/sub〉 QDs with good stability and water solubility were prepared by a facile and green hydrothermal method, and used to modify a glassy carbon electrode (WO〈sub〉x〈/sub〉 QDs/GCE). The proposed ECL sensor exhibited a stable and strong cathodic ECL signal when potassium peroxodisulfate (K〈sub〉2〈/sub〉S〈sub〉2〈/sub〉O〈sub〉8〈/sub〉) as the coreactant in aqueous solution. The possible ECL mechanism was studied and deduced, and the ECL response signal of the proposed sensor decreased rapidly in the presence of dopamine (DA). Under optimal conditions, the ECL signals of WO〈sub〉x〈/sub〉 QDs linearly decreased with the increase of DA concentration in the range of 10〈sup〉-15〈/sup〉 M to 10〈sup〉-9〈/sup〉 M and 10〈sup〉-9〈/sup〉 M to 10〈sup〉-5〈/sup〉 M, respectively. The detection limit was as low as 10〈sup〉-15〈/sup〉 M (S/N = 3). Based on these results, this method has been successfully applied to the determination of DA released by PC12 cells. The detection linear range for the detection of DA released by PC12 cells was from 0.1 to 0.9 μM with a detection limit of 0.045 μM. Therefore, the proposed ECL sensor displayed high sensitivity, good specificity and long-term stability, which may shed light on a new way to construct other high-performance ECL detection systems based on WO〈sub〉x〈/sub〉 or WO〈sub〉x〈/sub〉 QDs-based nanocomposites.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉A novel ultrasensitive electrochemiluminescence sensing platform based on water-soluble tungsten oxide quantum dots modified glassy carbon electrode (WO〈sub〉x〈/sub〉 QDs/GCE) using potassium peroxodisulfate (K〈sub〉2〈/sub〉S〈sub〉2〈/sub〉O〈sub〉8〈/sub〉) as the coreactant in aqueous solution was fabricated for the highly sensitive detection of dopamine released by cells.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019303472-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1061〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: Available online 26 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta〈/p〉 〈p〉Author(s): Sruti Chattopadhyay, Prabhjot K. Sabharwal, Swati Jain, Avneet Kaur, Harpal Singh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The quest for detecting bacteria has gained momentum in food and beverage industry for preventing spoilage of products to maintain requisite quality. The present paper describes the development of a SERS immunosensor for the detection of model pathogen, 〈em〉S. typhimurium〈/em〉 using strategically synthesized functionalized polymeric magnetic nanoparticles (FPMNPs) as effective capture probe and immunomagnetic separator. The synthesized probe contains surface diketonic functionalities which covalently link with amino groups of antibodies against 〈em〉Salmonella〈/em〉 common structural antigen (CSA-1-Ab) and hence specifically captured the target bacteria. Magnetic core of nanoparticles facilitated easy separation of target bacteria from the milieu of non-specific molecules. Gold nanoparticles (GNPs) modified with CSA-1-Ab and external Raman reporter molecules (RRM) were used as signal probes. We compared the signalling attributes of 4-mercapto benzoic acid (MBA) and 5,5΄-dithiobis(succinimidyl-2-nitrobenzoate) (DSNB) as RRMs. Capture and signal probes sandwich the target bacteria upon its addition, generating Raman signal from the 'hot-spots' created by signal probe. Under optimal conditions, the SERS intensities of MBA and DSNB at 1588 and 1336 cm〈sup〉-1〈/sup〉 respectively were used to measure the concentration of the pathogen in the range of 10〈sup〉1〈/sup〉-10〈sup〉7〈/sup〉 cells mL〈sup〉-1〈/sup〉. Limit of detection (LOD) of MBA and DSNB based immunosensor was measured as 100 cells mL〈sup〉-1〈/sup〉, and 10 cells mL〈sup〉-1〈/sup〉 respectively. Moreover, appreciable recovery (82-114%) was recorded for sensing method for different spiked food products. Thus, the developed magnetically assisted SERS immunosensor is sensitive, specific and has strong potential to be used for detecting contamination in food samples in field conditions.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267019303666-fx1.jpg" width="391" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1061〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: 21 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1051〈/p〉 〈p〉Author(s): Rory T. Steven, Michael Shaw, Alex Dexter, Teresa Murta, Felicia M. Green, Kenneth N. Robinson, Ian S. Gilmore, Zoltan Takats, Josephine Bunch〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Matrix assisted laser desorption ionisation mass spectrometry (MALDI-MS) at atmospheric pressure (AP) is, with a few notable exceptions, overshadowed by its vacuum based forms and AP transmission mode (TM) MALDI-MS lacks the up-take its potential benefits might suggest. The reasons for this are not fully understood and it is clear further development is required to realise the flexibility and power of this ionisation method and geometry. Here we report the build of a new AP-TM-MALDI-MSI ion source with plasma ionisation enhancement. This novel ion source is used to analyse a selection of increasingly complex systems from molecular standards to murine brain tissue sections. Significant enhancement of detected ion intensity is observed in both positive and negative ion mode in all systems, with up to 2000 fold increases observed for a range of tissue endogenous species. The substantial improvements conferred by the plasma enhancement are then employed to demonstrate the acquisition of proof of concept tissue images, with high quality spectra obtained down to 10 × 10 μm pixel size.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018313308-fx1.jpg" width="497" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 7 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1050〈/p〉 〈p〉Author(s): E.G. Lobanova, S.V. Lobanov〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Vibrational micro-spectroscopy is a powerful optical tool, providing a non-invasive label-free chemically specific imaging for many chemical and biomedical applications. However, hyperspectral image produced by Raman micro-spectroscopy typically consists of thousands discrete pixel points, each having individual Raman spectrum at thousand wavenumbers, and therefore requires appropriate image unmixing computational methods to retrieve non-negative spatial concentration and corresponding non-negative spectra of the image biochemical constituents. Here, we present a new efficient Quantitative Hyperspectral Image Unmixing (Q-HIU) method for large-scale Raman micro-spectroscopy data analysis. This method enables to simultaneously analyse multi-set Raman hyperspectral images in three steps: (i) Singular Value Decomposition with innovative Automatic Divisive Correlation which autonomously filters spatially and spectrally uncorrelated noise from data; (ii) a robust subtraction of fluorescent background from the data using a newly developed algorithm called Bottom Gaussian Fitting; (iii) an efficient Quantitative Unsupervised/Partially Supervised Non-negative Matrix Factorization method, which rigorously retrieves non-negative spatial concentration maps and spectral profiles of the samples' biochemical constituents with no 〈em〉a priori〈/em〉 information 〈em〉or〈/em〉 when one or several samples’ constituents are known. As compared with state-of-the-art methods, our approach allows to achieve significantly more accurate results and efficient quantification with several orders of magnitude shorter computational time as verified on both artificial and real experimental data. We apply Q-HIU to the analysis of large-scale Raman hyperspectral images of human atherosclerotic aortic tissues and our results show a proof-of-principle for the proposed method to retrieve and quantify the biochemical composition of the tissues, consisting of both high and low concentrated compounds. Along with the established hallmarks of atherosclerosis including cholesterol/cholesterol ester, triglyceride and calcium hydroxyapatite crystals, our Q-HIU allowed to identify the significant accumulations of oxidatively modified lipids co-localizing with the atherosclerotic plaque lesions in the aortic tissues, possibly reflecting the persistent presence of inflammation and oxidative damage in these regions, which are in turn able to promote the disease pathology. For minor chemical components in the diseased tissues, our Q-HIU was able to detect the signatures of calcium hydroxyapatite and 〈em〉β〈/em〉-carotene with relative mean Raman concentrations as low as 0.09% and 0.04% from the original Raman intensity matrix with noise and fluorescent background contributions of 3% and 94%, respectively.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018313564-fx1.jpg" width="356" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 21 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1049〈/p〉 〈p〉Author(s): Emma Pérez, Francisco M. Marco, Pascual Martínez-Peinado, Juan Mora, Guillermo Grindlay〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Haptens (i.e. biomolecules which molecular weight is lower than 10 kDa) determination by inductively coupled plasma mass spectrometry (ICP-MS) is usually performed by means of competitive immunoassays. In these immunoassays, analyte quantification is indirectly carried out using two different tracer species (i.e. antibodies or antigen-protein conjugates). However, the benefits (and drawbacks) derived from using a given tracer species have not been systematically investigated so far. The goal of this work is to evaluate the influence of the tracer species employed in competitive immunoassays on the analytical figures of merit for aflatoxin M〈sub〉1〈/sub〉 (AFM〈sub〉1〈/sub〉) determination in milk samples. To this end, three different strategies have been developed and evaluated, namely: (i) antibody binding inhibition assay (ABIA); (ii) capture inhibition assay (CIA); and (iii) capture bridge inhibition assay (CBIA). Experimental results show that the use of the antibody as tracer species (as in the ABIA approach) affords better analytical figures of merit for AFM〈sub〉1〈/sub〉 determination than using the antigen-protein conjugate as the tracer one (as in the CIA and CBIA strategies). The limit of detection afforded by ABIA strategy (i.e. 0.1 ng kg〈sup〉−1〈/sup〉) for AFM〈sub〉1〈/sub〉 determination was 1000-fold and 50-fold lower regarding the CIA and CBIA strategies, respectively. In the case of the ABIA approach, the characteristics of the metal nanoparticle label employed to detect the tracer species is critical on the analytical figures of merit. However, when the hapten-protein conjugates are used as tracer species, immunocomplex formation is severely hampered by steric effects caused by the protein moiety and, consequently, the characteristics of the metal nanoparticle label is not critical in the immunoassay performance. The different immunoassay strategies were successfully validated for AFM〈sub〉1〈/sub〉 determination in milk samples using a certified reference material of whole milk powder (ERM-BD283) according to European Conformity guidelines for analytical methods of food contaminants and mycotoxins. Compared to ELISA, the immunoassay developed for AFM〈sub〉1〈/sub〉 determination in milk samples improve limits of detection up to 10-fold.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018313631-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 21 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1051〈/p〉 〈p〉Author(s): Xiang-Ming Hu, Rong-Tian Li, Miao-Miao Zhang, Ke-Yang Wu, Huan-Huan Li, Nai-Han Huang, Bin Sun, Jin-Xiang Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A phenanthroline (phen) tethered berberine dimer 〈strong〉1〈/strong〉 is synthesized and further conjugated with carboxyfluorescein (FAM)-labeled single-stranded probe DNA (P-DNA) to give P-DNA@〈strong〉1〈/strong〉. The mutual interaction of these two components triggers the fluorescence quenching of FAM, and the non-emissive P-DNA@〈strong〉1〈/strong〉, in turn, functions as a sensor to detect cancer-associated microRNA-185 (miRNA-185), characterized by the FAM fluorescence recovery. The results show that P-DNA@〈strong〉1〈/strong〉 is capable of detecting miRNA-185 in 2 min with the detection limit of 0.2 nM. The detection mechanism was supported by fluorescence anisotropy, binding constant and molecular docking study. Competing experiments further indicate that P-DNA@〈strong〉1〈/strong〉 exhibits a high selectivity for miRNA-185 thus has a good potential in the diagnosis of related cancer at the early stage.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018313618-fx1.jpg" width="138" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 4 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1052〈/p〉 〈p〉Author(s): Chia-Lung Shih, Hsin-Yi Wu, Pao-Mei Liao, Jen-Yi Hsu, Chia-Yun Tsao, Victor G. Zgoda, Pao-Chi Liao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Urine and hair are used for assessing human exposure to toxicants. Urine tests can show acute toxicant exposure. Hair analysis can be used to determine chronic toxicant exposure after months to years; however, compared to urine, hair analysis in exposure assessments is much less frequently investigated. Urine and hair are different matrices, and their mechanisms of toxicant metabolite incorporation are different. The toxicant metabolites present in urine and hair may also be different. To clarify this issue, a procedure was developed to identify toxicant metabolites in rat samples using a mass spectrometry-based metabolomic data processing method. Di-(2-propylheptyl) phthalate (DPHP), an industrial plasticizer, was used as the model toxicant. The developed procedure identified not only known DPHP metabolites (mono-(propyl-6-oxo-heptyl) phthalate, mono-(propyl-6-hydroxyheptyl) phthalate, and mono-(propyl-6-carboxyhexyl) phthalate) but also novel metabolites that were structurally related to DPHP in the rat samples, indicating that the developed procedure successfully identified toxicant metabolites in 〈em〉in vivo〈/em〉 samples. Among the 62 tentative metabolites identified from the 7〈sup〉th〈/sup〉-day urine and the 28〈sup〉th〈/sup〉-day hair samples, 33 were detected in only the urine samples, 19 were detected in only the hair samples, and 10 were identified in both the urine and hair samples. A total of 15 out of the 62 metabolites were confirmed as DPHP structure-related metabolites based on MS/MS analysis. Among the 15 DPHP structure-related metabolites, only 2 metabolites were present in both the urine and hair samples. These results suggested that the metabolites identified in urine could not be applied to exposure assessments based on hair analysis.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018313473-fx1.jpg" width="219" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 4 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1052〈/p〉 〈p〉Author(s): Feng Tan, Xiao Jiang, Xianliang Qiao, Daming Sun, Jinsuo Gao, Xie Quan, Jingwen Chen, Suyu Ren, Yi Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A diffusive gradients in thin films (DGT) method using a new high-capacity cerium oxide (CeO〈sub〉2〈/sub〉) binding gel, for the first time, was developed for measuring dissolved inorganic arsenic in freshwater and seawater. The capacities of the new CeO〈sub〉2〈/sub〉 binding gel were 682 μg and 375 μg for As〈sup〉III〈/sup〉 and As〈sup〉V〈/sup〉, respectively. The masses of As〈sup〉III〈/sup〉 and As〈sup〉V〈/sup〉 accumulated by CeO〈sub〉2〈/sub〉-DGT device increased linearly with time and agreed well with the theoretical value calculated by DGT equation. The arsenic accumulation by CeO〈sub〉2〈/sub〉-DGT was independent of pH (4.05–9.04) and ionic strength (0.1–750 mM), and common anions including CO〈sub〉3〈/sub〉〈sup〉2−〈/sup〉, SO〈sub〉4〈/sub〉〈sup〉2−〈/sup〉, Cl〈sup〉−〈/sup〉 and PO〈sub〉4〈/sub〉〈sup〉3−〈/sup〉 had no obvious interference. CeO〈sub〉2〈/sub〉-DGT showed excellent long-term deployment performance in freshwater and synthetic seawater. Field trials with CeO〈sub〉2〈/sub〉-DGT achieved successfully the time-weighted-average concentrations of total inorganic arsenic in reservoir water (1.38 ± 0.09 μg/L) and coastal seawater (0.45 ± 0.06 μg/L). The results were comparable to those measured by grab sampling. The proposed method was reliable and robust for in-situ measurements of dissolved inorganic arsenic in environmental waters.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S000326701831362X-fx1.jpg" width="291" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 21 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1051〈/p〉 〈p〉Author(s): Yi Zhang, Daniel Yoke San Lee, Aysha Farwin, Jackie Y. Ying〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Particle-based assays are widely used in many biomedical applications. However, the performance of particle-based systems is often compromised by the carry-over contamination caused by the residual reagents during the liquid-exchange process. We have developed a sieve-through platform that utilizes a porous membrane to sieve out the particles, and an absorbent pad to remove the waste liquid by capillary force. The porous membrane is able to contain the liquid in the reaction chamber, and allows the waste liquid to flow through when it is brought into contact with the absorbent pad. The sieve-through platform is able to effectively remove the waste liquid, thereby achieving a more efficient liquid exchange as compared to the conventional process, and minimizing the carry-over contamination. In this study, we have determined the factors that affect the flow characteristics through the porous membrane on the sieve-through platform. We have shown that the sieve-through platform effectively reduces the carry-over contamination. In addition, we have shown particle-based ELISA on the sieve-through platform for the analysis of proteins and cells. We have further demonstrated the potential of the sieve-through platform for high-throughput analysis by presenting a sieve-array, which allows concurrent analysis of multiple samples in parallel. The sieve-through platform can significantly improve the performance of particle-based systems.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018313588-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 4 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1052〈/p〉 〈p〉Author(s): Jie Li, Yujia Sun, Cheng Chen, Tao Sheng, Peng Liu, Guanbin Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A smartphone-assisted microfluidic chemistry analyzer using an image-based colorimetric detection method was successfully developed for the simultaneous analysis of three diabetes- and hyperlipidemia-related indexes, glucose (GLU), triglyceride (TG), and total cholesterol (TC). A fan-shaped microfluidic chip was designed and optimized to reliably allocate a premixed serum sample into four reaction chambers by a simple pipetting. The color changes of the peroxidase-H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 enzymatic reactions in the chambers were captured and analyzed using a smartphone-controlled analyzer with a LED light source and a CCD camera. The highly quantitative relationships between the analyte concentrations and the color characteristic values of the green channel of the captured images were successfully established, enabling accurate and reproducible detections of GLU, TG, and TC simultaneously at a low cost. The parallel analyses of 111 serum samples using our system and a conventional chemistry analyzer were conducted, yielding an excellent correlation and consistency between these two systems. This study proved the feasibility of performing the multi-index monitoring of diabetes, hyperlipidemia, and other chronic diseases on a point-of-care platform at a high fidelity, but a low cost.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018313643-fx1.jpg" width="469" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 4 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1052〈/p〉 〈p〉Author(s): Veronika Šolínová, Lenka Žáková, Jiří Jiráček, Václav Kašička〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A new method, pressure assisted partial filling affinity capillary electrophoresis, has been developed to study noncovalent molecular interactions of the hexamer of human insulin (HI) with biologically relevant ligands, basic phenolic neurotransmitters serotonin and dopamine, basic amino acid arginine, and very weakly acidic phenol, in alkaline aqueous media. The apparent binding constants, 〈em〉K〈/em〉〈sub〉b〈/sub〉, of the HI-ligand complexes were determined from the dependence of the effective migration time changes of the above ligands on the variable zone lengths of HI hexamer dissolved in the background electrolyte (BGE) and hydrodynamically introduced into the bare fused silica capillary close to the UV detector. The strong cationic electroosmotic flow (EOF) in alkaline BGEs, 40/40 mM Tris/tricine, pH 8.1, and 25/34 mM NaOH/tricine, pH 8.5, with EOF mobilities 52.0 × 10〈sup〉−9〈/sup〉 and 58.0 × 10〈sup〉−9〈/sup〉 m〈sup〉2〈/sup〉V〈sup〉−1〈/sup〉s〈sup〉−1〈/sup〉, respectively, was reduced by the hydrodynamic counter flow induced by external pressure at the outlet capillary end to avoid expulsion of HI zone out of the capillary and to allow HI interaction with both cationic and anionic ligands inside the capillary. The HI hexamer interactions with the above ligands were found to be weak to moderately strong, with 〈em〉K〈/em〉〈sub〉b〈/sub〉 values in the range 385–1314 L mol〈sup〉−1〈/sup〉, and decreasing in the order HI-phenol 〉 HI-dopamine 〉 HI-serotonin 〉 HI-arginine.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018313655-fx1.jpg" width="369" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1053〈/p〉 〈p〉Author(s): Yongsheng Ji, Ruihong Lv, Shuhui Song, Junfeng Huang, Luwei Zhang, Guang Huang, Jinan Li, Junjie Ou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hydrophilic interaction chromatography (HILIC) utilizing zwitterion-modified material as solid phase has attracted extensive attention for selective enrichment of glycopeptides. However, a tedious synthesis and low specificity for glycopeptides have restricted its application. Herein, a facile and effective approach was developed to synthesize a zwitterionic (ZIC) polymer-coated magnetic composites (denoted as Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@PMSA) with a zwitterion ((2-(methacryloyloxy)ethyl)-dimethyl-(3-sulfopropyl) ammonium hydroxide, MSA) via one-step distillation-precipitation polymerization (DPP). The well-designed composites presented clearly ZIC-polymer shell and superior hydrophilicity (water contact angle 30.2), and the performance for selective enrichment of glycopeptides were investigated with standard and real samples, respectively. Owning to the abundant of ZIC molecules with multi-charge and polar groups on the surface of resulting polymer coating, the Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@PMSA demonstrated high selectivity for glycopeptides enrichment with IgG digest (twenty glycopeptides identified, S/N ≥ 20) and a mixture of IgG and BSA at the mass ratio of 1:230 (sixteen glycopeptides identified, S/N ≥ 20). Besides, the detection limit as low as 0.67 fmol for IgG (S/N ≥ 10) and satisfied recovery yield more than 74% were achieved by the proposed sorbents. Finally, the Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@PMSA was applied for enriching N-linked glycopeptides from human serum, and 348 unique N-glycosylation sites and 419 glycopeptides from 158 glycoproteins were strictly identified from 1 μL human serum. The results demonstrated that the proposed Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@PMSA showed a promising potential in glycoproteomics analysis of real biological samples.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018314235-fx1.jpg" width="366" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 4 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1052〈/p〉 〈p〉Author(s): Elise Rotureau, Pepita Pla-Vilanova, Josep Galceran, Encarna Companys, José Paulo Pinheiro〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The geochemical fate of indium in natural waters is still poorly understood, while recent studies have pointed out a growing input of this trivalent element in the environment as a result of its utilisation in the manufacturing of high-technology products. Reliable and easy-handling analytical tools for indium speciation analysis are, then, required. In this work, we report the possibility of measuring the total and free indium concentrations in solution using two complementary electroanalytical techniques, SCP (Stripping chronopotentiometry) and AGNES (Absence of Gradients and Nernstian Equilibrium Stripping) implemented with the TMF/RDE (Thin Mercury Film/Rotating Disk Electrode). Nanomolar limits of detection, 〈em〉i.e.〈/em〉 0.5 nM for SCP and 0.1 nM for AGNES, were obtained for both techniques in the experimental conditions used in this work and can be further improved enduring longer experiment times. We also verified that AGNES was able (i) to provide robust speciation data with the known In-oxalate systems and (ii) to elaborate indium binding isotherms in presence of humic acids extending over 4 decades of free indium concentrations.〈/p〉 〈p〉The development of electroanalytical techniques for indium speciation opens up new routes for using indium as a potential tracer for biogeochemical processes of trivalent elements in aquifers, 〈em〉e.g.〈/em〉 metal binding to colloidal phases, adsorption onto (bio)surfaces, etc.〈/p〉 〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S000326701831420X-fx1.jpg" width="388" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1053〈/p〉 〈p〉Author(s): Xueting Ren, Qingwang Xue, Liyuan Wen, Xia Li, Huaisheng Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Ideal methods for miRNA detection should be rapid and amplification-free in the mix-and-measure format. Here we report a novel FRET strategy based on fluorescence-enhanced p19 proteins-conjugated single quantum dot (QD) with multiplex antenna for one-step, specific and sensitive miRNAs quantitative analysis. It is simple in design and operation, and possesses high sensitivity and selectivity. In the strategy, RNA-binding viral p19 proteins-conjugated quantum dot (p19-QD) with high fluorescence and multiplex antenna was designed, and exploited for the capture recognition element and the donor. In the presence of target miRNAs, the p19-QD would tightly capture the miRNA-21-antimiRNA-21 duplex (dsRNA) formed in solution by hybridization of the specific antimiRNA-21-Cy3 probe (receptor) to the single-stranded miRNA-21 target. The FRET detection system between QD and Cy3 was constructed, and the signal read-out was measured. Conversely, in the absence of target miRNA-21, the p19-QD refuse to capture the free single-stranded antimiRNA-21-Cy3 probe (receptor), the FRET between quantum dot and Cy3 is deterred, thereby providing a low-background signal to improve sensitivity. Benefiting from the high affinity and specificity of p19 protein for duplex RNA and the fluorescence enhancement of donor p19-QD by the passivation and protection from p19 protein, a detection limit as low as 0.6 fM was achieved without employing any amplification techniques and pre-concentration or purification steps. The performance can be achieved by only one-step incubation without additional reagents and washing steps, thus greatly reducing the operating difficulty and saving time. Moreover, the fluorescence-enhanced p19-QD conjugate-based FRET strategy avoids the specific design in the number of the bases for interval in the DNA-QD conjugate-based FRET system using DNA strands as the FRET linker, and improves the FRET efficiency. Furthermore, it has been successfully applied to analyze the content of miRNA-21 in breast cancer cell. The results indicated that, the strategy will become a sensitive and reliable miRNAs quantification method in biomedical research and early clinical diagnostics.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018314193-fx1.jpg" width="496" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1053〈/p〉 〈p〉Author(s): Guangle Song, Aikun Liu, Hongli Jiang, Ruixue Ji, Jian Dong, Yanqing Ge〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A mitochondria-targeted ratiometric fluorescent probe based on hemicyanine and pyrido[1,2-a]benzimidazole was presented. It shows high sensitivity and selectivity toward SO〈sub〉2〈/sub〉 in pure water. The limit of detection (LOD) was as low as 26.7 nM, which is superior to most reported probes. Most importantly, the probe was successfully used for fluorescence imaging of endogenous bisulfite in mitochondria in Glioma cells.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018314107-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1053〈/p〉 〈p〉Author(s): Yu Cui, Xuewei Wang, Qi Zhang, Hao Zhang, Huahua Li, Mark Meyerhoff〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A 〈em〉S〈/em〉-nitrosothiol (RSNO) is used for highly selective and sensitive copper ion sensing for the first time. Cu(II) in the sample is reduced to Cu(I) by a low amount of thiols generated from hydrolysis of RSNO molecules or added thiols such as 〈span〉l〈/span〉-glutathione or 〈span〉l〈/span〉-cysteine. Cu(I) is able to trigger cleavage of the S〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉NO bond, which converts colored RSNOs to colorless products. The dark green 〈em〉S〈/em〉-nitroso-N-acetylpenicillamine is used as an exemplary RSNO in this report. In the spectrophotometric test, the detection limit toward Cu(II) is 0.23 μM without added thiol reductants, and 0.08 and 0.06 μM in the presence of 〈span〉l〈/span〉-glutathione and 〈span〉l〈/span〉-cysteine, respectively. Furthermore, we prepared fully inkjet printed paper-based sensors by deposition of all reaction reagents and buffers on the same piece of cellulose paper. A smartphone equipped with a color analysis app enables quantification of the color change of the paper-based Cu(II) sensors. In this method, a detection limit of 1.2 μM and a linear range of 0–10 μM were obtained. Finally, we successfully applied this instrumentation-free and reagent-free senor for Cu(II) analysis in real drinking water and river water samples.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018314089-fx1.jpg" width="294" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 4 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1052〈/p〉 〈p〉Author(s): Tong Zhou, Yongxin Song, Yapeng Yuan, Dongqing Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Traditionally, a resistive pulse sensor (also known as Coulter counter) works by letting a particle pass through a small orifice in an electrolyte solution. The detection sensitivity mainly relies on the volume ratio of the particle to the orifice. This paper presents a novel resistive pulse sensor which has a sensing orifice located on the side wall of a microchannel. In this way, the sensor can detect and count particles (or cells) without requiring particles (or cells) passing through the sensing gate. An equation was derived to relate the magnitudes of the detected signals and the electrical resistances. Results show that the magnitudes of the detected signals can be increased by applying voltages from more than one voltage input channels simultaneously. Under the same conditions, the magnitudes of the detected signals become larger when the diameters of particles are larger. Higher detection sensitivity can be obtained simply by increasing either the magnitudes of the applied voltages or the number of the voltage input channels, or reducing the opening of the side sensing gate to a size that is even smaller than the diameter of the particle. Due to the high detection sensitivity, detection of 1 μm particles by a relatively large sensing gate of 5 × 10 × 10 μm (width × length × height) was successfully demonstrated with a signal to noise ratio (S/N) of approximately 3. This sensor was also applied to detect and count human red blood cells and lymphocyte cells. Results show that this method can clearly distinguish the cells with different sizes based on the pre-determined-thresholds. Because this sensor does not require cells to pass through the sensing gate, the channel clogging problem can be avoided. More importantly, the detection sensitivity can be tuned by applying different voltages without fabricating a smaller sensing gate.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018314077-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 16 May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1056〈/p〉 〈p〉Author(s): Changhong Zhao, Xuebin Song, Weiguang Jin, Fan Wu, Qicheng Zhang, Ming Zhang, Ninglin Zhou, Jian Shen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The excellent anticancer effect of combined differential cancer therapies has been observed in the last few decades. Efficient theragnostic nanoparticles (NPs) for malignancy treatment have received considerable research attention and widely investigated today. This study presents our results on the development of aptamer-functionalized Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@carbon@doxorubicin NPs (Apt-Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@C@DOX) and their application in the synergetic chemo–photothermal therapy (PTT) of cancer. The Apt-Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@C@DOX NPs displayed high photothermal conversion efficiency and extensive pH/heat-induced drug release. 〈em〉In vitro〈/em〉 (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium) bromide experiments indicated that the combined chemo–PTT is much more toxic toward lung adenocarcinoma cells (A549) than PTT or chemotherapy alone. In addition, the Apt-Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@C@DOX NPs demonstrated decreasing contrast enhancement of magnetic resonance (MR) signals, which means they may be potentially applied as a contrast agent and serve as a critical component of T〈sub〉2〈/sub〉-weighted MR imaging of tumor tissues. Taking the results together, the Apt-Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@C@DOX NPs show great potential for cancer therapy.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉Schematic illustration for the preparation of Aptamer-Functionalized Cross-Linked Magnetic-Responsive Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@Carbon Nanoparticles (Apt-Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@C@DOX NPs) with tumor-triggered targeting property.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018314946-fx1.jpg" width="285" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 25 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1054〈/p〉 〈p〉Author(s): Ying Zhang, Wang Ren, Yu Zhu Fan, Jiang Xue Dong, Hui Zhang, Hong Qun Luo, Nian Bing Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A simple and label-free fluorescence turn-on method is proposed for the discrimination and detection of epinephrine (Ep) and dopamine (DA) via polyethyleneimine (PEI)-initiated in situ copolymerization and excitation wavelength switch. The PEI solution in the presence of Ep, DA and the mixture of Ep and DA are denoted as P〈sub〉Ep-PEI〈/sub〉, P〈sub〉DA-PEI〈/sub〉 and M〈sub〉Ep+DA〈/sub〉, respectively. In this study, PEI aqueous solution medium initiates the auto-oxidization of Ep and DA and the bioinspired copolymerization. These resultant copolymers emit yellow-green fluorescence color with a fluorescence emission maximum at 515 nm. Interestingly, these fluorescent copolymers exhibit distinct different excitation spectra, although Ep and DA are structurally very similar. P〈sub〉DA-PEI〈/sub〉 exhibits only one excitation peak at 385 nm, and P〈sub〉Ep-PEI〈/sub〉 shows dual-excitation mode with two significant excitation peaks at 328 nm and 405 nm, respectively. M〈sub〉Ep+DA〈/sub〉 also shows dual-excitation mode with two excitation peaks at 330 nm and 395 nm, respectively. Thus, individual Ep, DA, and their mixture can be discriminated based on the different excitation spectral shapes and peak locations of P〈sub〉Ep-PEI〈/sub〉, P〈sub〉DA-PEI〈/sub〉 and M〈sub〉Ep+DA〈/sub〉. Furthermore, the quantitative analysis of Ep and DA in mixture can also be achieved by switching excitation wavelength between 330 and 395 nm and monitoring the fluorescence emission intensity of M〈sub〉Ep+DA〈/sub〉 at 515 nm. The fluorescence intensity of M〈sub〉Ep+DA〈/sub〉 only related to the concentration of Ep when excited at 330 nm. Moreover, the concentration of DA can also be calculated by subtracting the fluorescence intensity of P〈sub〉Ep-PEI〈/sub〉 from the total fluorescence intensity when excited at 395 nm. The resultant method has been used to simultaneously detect Ep and DA in human urine samples. The proposed fluorescence system is facile, eco-friendly, low-cost, and time-saving, and also provides a new and simple path for discriminating analogues.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S000326701831479X-fx1.jpg" width="305" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 25 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1054〈/p〉 〈p〉Author(s): Nina Denver, Shazia Khan, Ioannis Stasinopoulos, Colin Church, Natalie ZM. Homer, Margaret R. MacLean, Ruth Andrew〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Estrogens regulate many diverse biological processes in health and disease. They circulate at a wide range of concentrations in females generating several active metabolites (hydroxy and methoxyestrogens). The metabolites are assumed to be present in much lower levels and are thought to contribute to diseases such as pulmonary arterial hypertension (PAH). Estrogen metabolites are challenging to quantify in plasma and currently available immunoassays are non-specific. Here we have developed and validated a novel assay to simultaneously quantify parent estrogens and their metabolites by mass spectrometry (MS).〈/p〉 〈p〉Estrogens were extracted from human plasma using solid phase extraction and derivatized using 1-(5-fluoro-2, 4-dinitrophenyl)-4-methylpiperazine (PPZ) before quaternization by methylation (“MPPZ”). MPPZ derivatives were separated and quantified by liquid chromatography tandem MS (LC-MS/MS) in positive electrospray ionization mode, using a QTrap 6500 + coupled to a Shimadzu Nexera X2. Separation was achieved using an ACE Excel 2 C18-PFP column (2 μm, 2.1 mm × 150 mm). The limits of quantification (LOQ) were 0.43–2.17 pg on column with a linear range from 2 or 10 - 2000 pg mL〈sup〉-1〈/sup〉. Intra and inter-day precision and accuracy were acceptable (〈20% at LOQ and 〈15% above). These derivatives demonstrated minimal degradation upon short-term storage at 15 °C (〈20%) and longer term at −20 °C (〈20%). Using this approach, estrone (E1) and estradiol (E2) were detected in plasma (0.5 mL) from healthy women and those with PAH but downstream metabolites 16-hydroxy-E1, 16-hydroxy-E2, 2-methoxy-E1 and 4-methoxy-E1 were only detected in plasma from diseased patients. These findings will next be tested robustly in large patient cohorts.〈/p〉 〈p〉This novel LC-MS/MS analysis of estrogens and their bioactive metabolites, using MPPZ derivatization, opens doors for the simultaneous analysis of a panel of estrogens in human plasma, across the endogenous range of concentrations encountered in health and disease.〈/p〉 〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018314727-fx1.jpg" width="434" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 9 May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1055〈/p〉 〈p〉Author(s): Qingwei Huang, Chuan He, Jinli Zhang, Wei Li, Yan Fu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Carboxylic acids have been efficiently used to activate H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 to form even more potent oxidant-peroxy acids through enzyme-catalyzed processes. By employing acetic acid as the activator, herein we report for the first time that cofactor-free DNA displays unexpected activity in H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉-mediated oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) under mild conditions. A series of 10-nt oligonucleotides were rationally designed with various combinations of double nucleotides including TG, AG, CG, TA and AC respectively, which demonstrates that the catalytic performance of DNA is highly dependent upon the sequence composition, strand length and continuous nucleotides. Inspired by phosphate-induced inhibition effects on the formation of peracetic acid, an ultrasensitive assay was well-established for monitoring alkaline phosphatase (ALP) on the basis of double terminal-phosphorylated G-rich oligonucleotides. Phosphorylated DNA not only serves as the substrate for ALP-catalyzed hydrolysis, but also acts as the enzyme-like catalyst for signal amplification. Quantitative determination of ALP is realized in a linear range from 0.05 to 15 mU/mL, resulting in the limit of detection of 0.01 mU/mL. The rapid and reliable test also has great potential in analyzing serum samples for practical disease diagnosis.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018314843-fx1.jpg" width="343" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 9 May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1055〈/p〉 〈p〉Author(s): Yucai Yang, Yue Huang, Chao Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Here we report an electrochemical DNA (E-DNA) sensor to detect a variety of analytes by using a novel interfacial probe that rationally integrates triplex-forming oligonucleotide (TFO) into a tetrahedral DNA nanostructure (TDN). In the presence of analyte, the blocked TFO is released and subsequently binds the edge of TDN to form a triplex DNA structure, which confines the redox reporter to be in close proximity to the underlying electrode and enhances the electrochemical signal. Thanks to the unique design and property of the probe, the proposed sensor could efficiently suppress the background signal (from 0.69 μA to 0.092 μA) and thus enhance the signal-to-noise ratio, resulting in improved sensing performance. Furthermore, the sensor displays new merits such as rapid response (∼35 min), one-step operation, easy regeneration (buffer change) and good generality (changing recognition element) compared with traditional TDN-based E-DNA sensor using enzyme displays signal transducer. In addition, to demonstrate real-world applicability of this new sensor, we have successfully detected different analytes (e.g., DNA, protein, and metal ion) in the complex media (e.g., serum, blood, and lake water), implying its considerable potential for precise bioanalysis in the future.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉An electrochemical DNA (E-DNA) sensor to detect a variety of analytes by using a novel interfacial probe that rationally integrates triplex-forming oligonucleotide (TFO) into a tetrahedral DNA nanostructure (TDN) was developed.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018314806-fx1.jpg" width="440" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 9 May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1055〈/p〉 〈p〉Author(s): Amrita Soni, Chandra Mouli Pandey, Manoj Kumar Pandey, Gajjala Sumana〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, polyaniline nanospindles have been synthesized using iron oxide as sacrificial template. These nanospindles were utilized for the fabrication of PANI-MoS〈sub〉2〈/sub〉 nanoflower architectures 〈em〉via〈/em〉 hydrothermal route. The electrostatic interaction between PANI and MoS〈sub〉2〈/sub〉 improves the conductivity and provides more direct paths for charge transportation. SEM, TEM, XRD, Raman Spectroscopy techniques were employed to explore the crystal structure, and morphological properties of the PANI-MoS〈sub〉2〈/sub〉 nanocomposite. Furthermore, an electrochemical biosensing platform based on PANI-MoS〈sub〉2〈/sub〉 nanocomposite was fabricated for the specific detection of chronic myelogenous leukemia (CML) by using electrochemical impedance spectroscopy technique. The binding interactions between the pDNA/PANI-MoS〈sub〉2〈/sub〉/ITO bioelectrode and target DNA sequence were also studied. The biosensor exhibits high sensitivity and wide detection range (10〈sup〉−6〈/sup〉  M to 10〈sup〉−17〈/sup〉  M) of target DNA with low detection limit (3 × 10〈sup〉−18〈/sup〉  M). Additionally, the specificity studies of the genosensor with various target DNA sequences (complementary, noncomplementary and one base mismatch) and real samples analysis of CML shows its potential for clinical diagnostics.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S000326701831482X-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 25 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1054〈/p〉 〈p〉Author(s): Chuanhui Huang, Yujie Wang, Qiao Huang, Yu He, Lan Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Microcystins (MCs), which are produced by eruptive cyanobacteria, seriously threaten the health of humans for their poisonousness. Herein, a facile strategy was introduced to synthesize the magnetic γ-cyclodextrin polymer (Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@PDA@γ-CDP) composite and set it as a novel adsorbent with excellent properties for the magnetic solid-phase extraction (MSPE) of MCs. The prepared Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@PDA@γ-CDP microspheres exhibit good aqueous dispersibility and highly affinity for MCs, thus contribute to an excellent extraction performance for trace MCs in water samples. Combined with HPLC–MS/MS, a handy, sensitive and efficient method was developed for detection of MCs in water samples, which shows good linearity (R〈sup〉2〈/sup〉 ≥ 0.9992) in the range of 1.0–1000 pg mL〈sup〉−1〈/sup〉, low limits of detection (0.8–2.0 pg mL〈sup〉−1〈/sup〉, S/N = 3), satisfactory repeatability with the relative standard deviations (RSDs) lower than 6.2% (n = 5). At last, the proposed method was successfully applied for the extraction and detection of MCs in fresh water and sea water samples, which provides great potential of trace-level MCs determination in lake and sea water.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018314776-fx1.jpg" width="364" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 9 May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1055〈/p〉 〈p〉Author(s): Ga-Yeon Lee, Ji-Hong Bong, Ji Yun Kim, Gu Yoo, Min Park, Min-Jung Kang, Joachim Jose, Jae-Chul Pyun〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The autoimmune diseases systemic lupus erythematosus (SLE) and Sjogren's syndrome (SS) are diagnosed by detection of autoantibodies against Ro and La protein autoantigens, respectively. In this work, the diagnosis of autoimmune diseases SLE and SS was demonstrated using thermophoresis of 〈em〉Escherichia coli〈/em〉 with the autodisplayed autoantigens. Ro and La protein autoantigens were autodisplayed by constitutive expression together with a fluorescent protein called tdTomato in the cytosol. The binding affinity of the autodisplayed autoantigens was tested against positive and control sera by using FACS as a reference method. The factors influencing interactions between 〈em〉E. coli〈/em〉 with autodisplayed autoantigens and autoantibodies in sera during thermophoresis were analyzed by measurement of cell surface charge and size before and after interaction. Finally, the thermophoretic diagnosis of autoimmune diseases SLE and SS was demonstrated using sera from patients afflicted with the respective diseases by estimating sensitivity and selectivity from ROC plots.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018314879-fx1.jpg" width="272" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 25 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1054〈/p〉 〈p〉Author(s): S.E. Janssen, R.F. Lepak, M.T. Tate, J.M. Ogorek, J.F. DeWild, C.L. Babiarz, J.P. Hurley, D.P. Krabbenhoft〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The precise quantification of mercury (Hg) stable isotope compositions in low concentration or dilute samples poses analytical challenges due to Hg mass limitations. Common Hg pre-concentration procedures require extended processing times, making rapid Hg stable isotope measurements challenging. Here we present a modified pre-concentration method that combines commonly used Hg reduction and gold trap amalgamation followed by semi-rapid thermal desorption (less than 1 h) and chemical trapping. This custom designed system was demonstrated to perform adequately on multiple trapping matrices including a new bromine monochloride (BrCl) wet oxidant trap (40% 3HNO〈sub〉3〈/sub〉:BrCl), capable of trapping consistently in 2 mL volume over a wide range of Hg masses (5–200 ng). The procedure was also shown to work effectively on natural matrices, waters and sediments, producing comparable isotope results to the direct digestion analyses. Here, we present a method that can effectively triple sample throughput in comparison to traditional procedures, and also access lower concentration matrices without compromising the accuracy or precision of Hg isotope measurements.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018314752-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 9 May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1055〈/p〉 〈p〉Author(s): Lian Ma, Qiaran Zhang, Chao Wu, Yue Zhang, Lintao Zeng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Composite nanomaterials are particularly useful and offer many excellent opportunities for electrochemical sensing application. Depending on the high catalytic activity of bimetallic nanoparticles, the large specific surface area, abundant active edges and co-catalytic function of MoS〈sub〉2〈/sub〉 nanosheets, we, for the first time, prepared a novel PtNi bimetallic nanoparticles loaded MoS〈sub〉2〈/sub〉 nanosheets (PtNi@MoS〈sub〉2〈/sub〉) hybrid material by a co-reduction method for the electrochemical sensing application. The nanocomposite is characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS), and then casted on a bare glassy carbon electrode (GCE) to fabricate an electrochemical sensor (PtNi@MoS〈sub〉2〈/sub〉/GCE). The electrochemical investigation showed that the sensor performed good selectivity and wide linear ranges for the simultaneous detection of dopamine (0.5–150 μM) and uric acid (0.5–600 μM). And the detection limits were down to 0.1 μM (S/N = 3) for both analytes.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉For the first time, a nanocomposite of PtNi bimetallic naoparticles loaded MoS〈sub〉2〈/sub〉 nansheets was prepared by a co-reduction method and was used to establish an electrochemical sensor for the simultaneous detection of dopamine and uric acid. The sensor showed excellent performance and had been successfully applied for the simultaneous determination of the two analytes in human urine samples.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018314740-fx1.jpg" width="450" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 9 May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1055〈/p〉 〈p〉Author(s): Yongfeng Ning, Xu Cui, Chao Yang, Fengxiang Jing, Xiaojun Bian, Lin Yi, Gang Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We present a self-discretization and zero-water-loss microfluidic digital PCR (dPCR) device to enable low-cost and robust quantitative nucleic acid assays. In this device, a thin void is integrated beneath the reaction chamber array. By utilizing the permeability of polydimethylsiloxane (PDMS) film, the integrated void serves a dual function: vacuum “accumulator” and hydration “reservoir”. The combination of pre-stored pumping energy and water compensation for evaporation loss enables simple, robust and reliable single-DNA-molecule amplification and detection in 10,000 reactors of picoliter volume. Compared to the conventional degassing PDMS pumps, the vacuum accumulator exhibits superior performance due to more vacuum storage and shorter diffusion distance. We also evaluated the performance of the embedded hydration layer in suppressing evaporation loss at elevated temperatures, and verified that zero-water-loss could be achieved for all reaction chambers in our dPCR chip during thermal cycling. By performing quantitative detection of T790M DNA from 10 to 10〈sup〉4〈/sup〉 copies/μL, the proposed dPCR chip demonstrated high accuracy and excellent performance for the absolute quantification of the target gene with a dynamic range of 10〈sup〉4〈/sup〉. The simplicity and robustness of our dPCR chip make it well suited for low-cost molecular diagnostic assays under resource-limited settings.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018314788-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1053〈/p〉 〈p〉Author(s): Jiří Šalplachta, Marie Horká, Karel Šlais〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Amphotericin B (AmB) is still, despite its severe nephrotoxicity, the first-line agent in the management of serious systemic fungal infections. A sensitive and reliable method is therefore required to control AmB concentration in body fluids of a patient. This study demonstrates the potential of the off-line combination of preparative isoelectric focusing (IEF) with capillary isoelectric focusing (CIEF) or capillary zone electrophoresis (CZE) in the determination of AmB in human blood serum. The required value of the isoelectric point of AmB was determined to be 6.1 using the CIEF technique. Preparative IEF served as a pre-separation and concentration technique. The pH gradient was traced by colored low molecular p〈em〉I〈/em〉 markers. The collected fraction with AmB was easily processed and then analyzed by CIEF and CZE. Tens of picograms of AmB in human blood serum sample can be determined by a combination of preparative IEF with CZE. The method was linear in the AmB concentration range of 0.3–600 ng mL〈sup〉−1〈/sup〉. The recovery ranged from 93% to 98%.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018314454-fx1.jpg" width="496" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 25 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytica Chimica Acta, Volume 1054〈/p〉 〈p〉Author(s): Lingjun Ma, Christoph Bueschl, Rainer Schuhmacher, Andrew L. Waterhouse〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Quinones are key reactive electrophilic intermediates that are formed in abundance during wine oxidation and have a significant impact on wine character, altering color and flavor. They readily react with nucleophiles, such as SO〈sub〉2〈/sub〉 and glutathione. Some nucleophiles have been reported to react with quinones in model wines, but many of the corresponding products have not been confirmed in real wines. Here, a stable isotope labeling approach employing 〈sup〉13〈/sup〉C〈sub〉6〈/sub〉 labeled 〈em〉ortho〈/em〉-quinone was evaluated in combination with an exact-mass list of putative products. The measurements were taken using high performance liquid chromatography coupled to time-of-flight mass spectrometry. Fourteen compounds were detected based on a match in the table plus an M+6 mass isotope pattern derived from the labeled quinone mixture. The presence of the mass label also establishes reaction pathways for the formation of these compounds, and suggests how wine catechols could react during wine oxidation, demonstrating the insight provided by this analytical technique.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉Ma et al., Tracing oxidation reaction pathways in wine using 13C isotopolog patterns and a putative compound database.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0003267018314545-fx1.jpg" width="394" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉