ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Column liquid chromatography  (80)
  • Springer  (80)
  • American Geophysical Union
  • Hindawi
  • 2010-2014
  • 1995-1999  (80)
  • 1996  (80)
Collection
Keywords
Publisher
  • Springer  (80)
  • American Geophysical Union
  • Hindawi
Years
  • 2010-2014
  • 1995-1999  (80)
Year
  • 1
    Electronic Resource
    Electronic Resource
    High performance liquid chromatography —Electrospray tandem mass spectrometry (HPLC-ESI-MS-MS) for the analysis of heterocyclic aromatic amines (HAA) (1996)
    Springer
    Chromatographia 42 (1996), S. 7-11 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Heterocyclic aromatic amines (HAA) ; Electrospray MS-MS detection ; Selected reaction monitoring (SRM)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Sensitive and selective detection of the sixteen most abundant heterocyclic aromatic amines (HAA) has been achieved by application of high performance liquid chromatography-electrospray tandem mass spectrometry (HPLC-ESI-MS-MS) in combination with selected reaction monitoring (SRM). Detection limits between 0.1 and 50 ng mL−1 were established by use of HAA model solutions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02271047
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The optimization of step-gradient elution conditions in liquid chromatography: Application to pesticide residue analysis using coupled-column reversed-phase LC (1996)
    Springer
    Chromatographia 42 (1996), S. 17-24 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Column switching ; Step-gradient elution ; Optimization ; Trace analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A computer spreadsheet application has been developed for the optimization of step-gradient elution conditions as applied in coupled-column RPLC for online clean-up and separation in the analysis of pesticide residues. The procedure is based on the experimentally determined retention behaviour of the analytes as a function of mobile phase composition. Retention and peak volumes of the analytes eluting under isocratic and one- and/or two-step gradient conditions can be calculated. For a given set of analytes, the spreadsheet systematically calculates the resolution of the least efficiently separated pair of peaks in the space defined by the eluotropic strengths of the mobile phases and the time at which the step-gradient takes place. The performance of the proposed procedure was tested and evaluated for the analysis of nine polar pesticides for which in a previous study adequate conditions had been found by computer-aided chromatogram simulation. the optimum conditions predicted by the procedure were in good agreement with those established experimentally and by simulation. The simultaneous production of data on retention, peak volume and resolution for a group of analytes under selected one- and/or two step-gradient elution conditions makes the calculation procedure highly productive and flexible in searching for and/or adjusting appropriate separation conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02271049
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Determination of the specific interaction of disubstituted aromatic compounds on hydrous zirconium oxide-loaded porous polymer resin (1996)
    Springer
    Chromatographia 42 (1996), S. 396-400 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Hydrous zirconium oxide ; Porous polymer resin ; Disubstituted phenols ; ortho-Benzoic acid derivatives
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A porous polymer resin loaded with hydrous zirconium oxide (Zr-gel) was evaluated as a stationary phase for the liquid chromatographic separation of disubstituted aromatic compounds. The prepared Zr-gel was used to separate disubstituted phenols andortho-substituted benzoic acid derivatives in reversed-phase mode. The retention time of catechol was greater than those of other disubstituted phenols; this implies that the Zr-gel has specificity for the phenolic hydroxyl group. The retention behavior ofortho-substituted benzoic acid derivatives on the Zr-gel was also evaluated in reversedphase mode using buffer. Phthalic acid was specifically retained in the vicinity of pH 6.0, which has been regarded as the equal adsorbic point. Similar behavior was also observed for salicylic acid, although the retention time of salicylic acid was less than that of phthalic acid. It seems that the specific retention behavior of hydrous zirconium oxide is a result of complexation with ligands such as hydroxyl and carboxyl groups. The results of this study have revealed that the retention mechanism of hydrous zirconium oxide is a combination of ion exchange and interaction based on complexation with ligands.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02272129
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    HPLC determination of tryptophan enantiomers with photometric, fluorimetric and diode-laser polarimetric detection (1996)
    Springer
    Chromatographia 42 (1996), S. 494-498 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Tryptophan ; Chiral separations ; Diode-laser polarimetric detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The combined utilization of photometric, fluorimetric and polarimetric detection liquid chromatography detectors in series for the identification and quantification of D-tryptophan and L-tryptophan was evaluated. Detection limits of about 1 μg were established with the range of linearity extending to about 100 μg. The relative standard deviation of the D-form and L-form tryptophan were 7.32 and 4.22%, respectively. The amount unknown of tryptophan enantiomers in the different mixtures was determined with an accuracy of 1.58% at the 40 μg injection level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02290282
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Chroamtographic behaviour of un-sulphated and sulphated oligoethyleneglycol nonylphenyl ether surfactants in normal-phase liquid chromatographic systems containing water (1996)
    Springer
    Chromatographia 42 (1996), S. 539-546 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Un-sulphated and sulphated surfactants ; Oligoethyleneglycol nonylphenyl ethers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Retention behaviour of un-sulphated and sulphated, oligoethyleneglycol nonylphenyl ether, anionic surfactants was investigated in normal-phase LC systems with chemically bonded amino stationary phase in organic mobile phases containing water and cetyl trimethylammonium bromide (CTAB). Addition of water to the mobile phase improves efficiency of separation and linearity of the dependences of logk′ versus number of oxyethylene units in the sulphated oligomers, so that it is possible to describe simultaneous effects of this number and of the concentration of CTAB on retention by a simple equation. In this system, it is possible to separate lower sulphated and un-sulphated oligomers in a single run in 10–15 min under isocratic conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02290288
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Identification of vitamin B12 analogues by liquid chromatography with electrothermal atomic absorption detection (1996)
    Springer
    Chromatographia 42 (1996), S. 566-570 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Electrothermal atomic absorption spectrometry ; Vitamin B12 analogues ; Cobalamins and cobalt ; Meat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The coupling of liquid chromatography and electrothermal atomic absorption spectrometry (LC-ETAAS) lowers the detection limit for identification of vitamin B12 analogues. Cobalamins and aqueous cobalt (II) were separated by reversed-phase liquid chromatography using a linear gradient: 26∶74 (v/v) methanol:0.05 M phosphate buffer (pH 4.2) to 50∶50 mixture over 8 min. The vitamins were quantitatively determined in the column effluent by measuring total cobalt by ETAAS. The analysis of meat and liver extracts by LC-ETAAS showed that the matrix did not interfere with the determination of cobalt. Hence, recoveries of cobalt in spiked meat and liver samples were satisfactory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02290293
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    High-performance liquid chromatographic determination of meropenem in rat plasma using column-switching (1996)
    Springer
    Chromatographia 42 (1996), S. 405-408 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Meropenem in rat plasma ; Column-switching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The purpose of this study was to develop a columnswitching HPLC method for the determination of meropenem in plasma. This method showed excellent precision and accuracy with good sensitivity and speed. The total analysis time per sample was less than 20 min and the mean coefficients of variation for intra- and inter-assay were less than 4.0%. The method has been successfully applied to plasma samples from rats receiving an intraperitoneal injection of meropenem.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02272131
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    1,1′-[Ethenylidenebis(sulfonyl)]bis-benzene: A useful pre-chromatographic derivatization reagent for HPLC analysis of thiol drugs (1996)
    Springer
    Chromatographia 42 (1996), S. 515-520 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Thiol drugs ; Pre-chromatographic derivatization ; 1,1′-[ethenylidenebis(sulfonyl)]bis-benzene reagent
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The use of 1,1′-[ethenylidenebis(sulfonyl)]bis-benzene as a pre-chromatographic reagent for LC analysis of thiol drugs is proposed. The reagent reacts rapidly (2 min) under mild conditions (pH 7.5, ambient) with thiol drugs and the resulting adducts can be chromatographed under reversed-phase conditions (C-18 column). Excess reagent can be removed from the reaction mixture by simple liquid-liquid extraction with chloroform. The HPLC method using UV detection was successfully applied to the analysis of reduced glutathione (GSH), N-acetylcysteine, N-2-mercaptopropionylglycine and captopril in their commercial formulations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02290285
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Direct enantiomeric HPLC separation of several 2-arylpropionic acids, barbituric acids and benzodiazepines on chiralcel OJ-R chiral stationary phase (1996)
    Springer
    Chromatographia 43 (1996), S. 599-606 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; 2-Arylpropionic acids ; Barbituric acids ; Benzodiazepines ; Cellulose tris(4-methylbenzoate) chiral stationary phase ; Reversed-phase mode ; Chiral recognition mechanisms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A newly developed reversed-phase chiral stationary phase, cellulose tris(4-methylbenzoate), known as Chiralcel OJ-R, has been successfully applied to the direct resolution of the enantiomers of several nonsteroidal anti-inflammatory drugs belonging to the profen group. Among the five barbituric acids tested, the chiral resolution of mephobarbital is especially high. The Chiralcel OJ-R column also proved quite efficient for the enantiomeric resolution of a few representatives of the benzodiazepine group. Variations of mobile phase conditions based on acetonitrile and/or methanol were tested. The results obtained are briefly compared with separations performed using a Chiralcel OJ column under normalphase conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02292974
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Extraction and identification procedures of polyphenolic compounds and carbohydrates in phillyrea (Phillyrea angustifolia L.) leaves (1996)
    Springer
    Chromatographia 42 (1996), S. 571-577 
    Details
    ISSN: 1612-1112
    Keywords: Liquid-liquid and liquid-solid extractions ; Column liquid chromatography ; Mass spectrometry detection ; Flavonoids inPhillyrea angustifolia leaves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Liquid-liquid (LLE) and liquid-solid extraction (LSE) procedures were developed to identify polyphenols in phillyrea (Phillyrea angustifolia L.) leaves. The liquidsolid extraction, carried out by using two serial Bond-Elut® CH and Bond-Elut® SAX cartridges allowed the collection of both polyphenols and soluble carbohydrates during a single extraction of leaf. This method seems to be suitable for both phytochemical and physiological study of the species, allowing the identification of two classes of organic compounds which have a central role in the metabolism of phillyrea plants. A method of isolation and concentration of polyphenols for further molecular characterization, using centrifuge chromatography, was also developed. Molecular characterization, carried out by UV-Vis spectrophotometry and mass spectrometry, demonstrated the presence of compounds with interesting biological activity, i.e. flavonoids and oleuropein derivatives. The soluble carbohydrate composition of phillyrea leaves did not substantially differ from that ofOlea europaea L. leaves, except for a higher mannitol/glucose ratio. This carbohydrate distribution may be linked to the evolution pattern of this species which usually grows in severely stressed environments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02290294
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Simultaneous separation and identification of hashish constituents by coupled liquid chromatography-mass spectrometry (HPLC-MS) (1996)
    Springer
    Chromatographia 43 (1996), S. 129-134 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; On-line liquid chromatography-mass spectrometry ; Neutral and acidic cannabinoids ; Hashish samples
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary This paper reports the use of liquid chromatography for the separation and determination of the major cannabinoids extracted from hashish samples. The direct coupling to the mass spectrometer enables the selective identification both of neutral and acidic cannabinoids. The developed method does not require any preliminary derivatization and should, therefore, be of interest in forensic analysis for simple and unequivocal determination of hashish constituents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02292940
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Effect of solute association on the apparent adsorption isotherm. A model of the separation of non-racemic mixtures of enantiomers in achiral chromatographic systems (1996)
    Springer
    Chromatographia 43 (1996), S. 17-24 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Non-linear adsorption isotherm ; Simulation of chromatographic peak profiles ; Separation of optical isomers ; Non-racemic mixtures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary This article discusses the effect of solute association on the apparent adsorption isotherm and on the chromatographic peak profile. The modelling performed has shown that dimerization of a solute in a chromatographic system gives rise to an apparent adsorption isotherm of the non-linear type. This results first of all in peak broadening. Tailing or a fronting can be observed depending on the relative retention of the monomer and the dimer. Secondly, the retention of the solute depends on the amount of sample because of the non-linear character of the adsorption isotherm. As a result, an excess of one of two analytes with absolutely identical adsorption properties i.e. optical isomers, can be separated in such chromatographic systems by considering that the sample contains non-equal amounts of two analytes. The phenomenon is illustrated by simulated chromatograms of the separation of non-racemic mixtures of enantiomers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02272816
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Evaluation of the influence of the base material loaded with hydrous zirconium oxide gel on the retention behavior of disubstituted benzoic acids (1996)
    Springer
    Chromatographia 43 (1996), S. 79-81 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Hydrous zirconium oxide ; Porous polymer resin ; Silica gel ; ortho-Benzoic acid derivatives
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Silica gel loaded with hydrous zirconium oxide (Zr-gel-S) has been prepared and the influence of the base material on the retention behavior ofo-phthalic acid on the hydrous zirconium oxide was evaluated. The retention behavior of the acid on the Zr-gel-S was compared with that on Zr-gel-5, the polymer-based Zr-gel. Comparable retention behavior,i.e. maximum retention in the vicinity of pH 6, which has been regarded as the equal adsorbic point, was observed for both types of Zr-gel, although there was a large difference in the retention times. The difference in retention on the two types of Zr-gel could be ascribed to nature of the base material. The results in this experiments showed, however, that the specific behavior at pH 6 was an essential characteristic of hydrous zirconium oxide and was not related to the influence of the base materials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02272826
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Normal and reversed-phase HPLC for more complete evaluation of tocopherols, retinols, carotenes and sterols in dairy products (1996)
    Springer
    Chromatographia 43 (1996), S. 89-93 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Sterols, tocopherols, retinols and carotenes ; Dairy products
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary We have previously described a normal-phase HPLC method for the simultaneous determination of α, β, γ and δ tocopherol, thecis andtrans isomers of retinol, and total carotenes in different Italian cheeses and milk. In this paper we describe a reversed-phase HPLC method using solely methanol as the mobile phase for the determination of α-tocopherol, β-+γ-tocopherols, total retinols, cholesterol, β-sitosterol, campesterol and stigmasterol, and α- and β-carotene. The method developed has been applied to some new dairy products such as natural Quark, with olive, basil or banana and to processed cheese with tomato and the results have been compared with the corresponding results obtained by the normal-phase method. The conclusion is that more complete evaluation of the tocopherol, retinol, carotene and sterol content of dairy products, especially when vegetables and fruits are present, is necessary and can be obtained using both the normal- and reversed-phase HPLC methodologies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02272829
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Determination of pesticides by on-line trace enrichment-reversed-phase liquid chromatography-diode-array detection and confirmation by particle-beam mass spectrometry (1996)
    Springer
    Chromatographia 43 (1996), S. 592-598 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Diode-array detection ; Particle beam mass spectrometric detection ; Pesticides in water ; On-line solid-phase extraction (SPE)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A group of pesticides has been determined by liquid chromatography with diode-array detection (DAD). The coupling of a particle-beam (PB) mass spectrometer to the outlet of the DAD enabled the identities of the pesticides to be confirmed from mass spectra obtained by electron impact ionization. On-line trace enrichment of 200 mL of sample with a PLRP-S precolumn enabled most pesticides to be determined in real samples at levels between 0.2 and 5 μg L−1 and with limits of detection (LOD) between 0.05 and 0.5 μg L−1. In the analysis of real samples, one of the pesticides studied was determined by DAD and its identity was confirmed by comparison of PB mass spectra. The use of PB-MS also enabled the detection of non-target compounds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02292973
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Comparative study of the use of high-performance liquid chromatography and capillary electrophoresis for determination of phenolic compounds in water samples (1996)
    Springer
    Chromatographia 43 (1996), S. 619-624 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Capillary electrophoresis ; Phenolic compounds ; Water samples
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A comparative study of high-performance liquid chromatography (HPLC) and capillary zone electrophoresis (CZE) for determination of eleven EPA priority phenols in water samples is discussed. The repeatability, linearity and detection limits of both methods are compared. A solid-phase extraction method using a highly cross-linked styrene-divinylbenzene copolymer sorbent is used for the off-line preconcentration process in order to determine these compounds in water at low levels. Both methods are used to determine phenolic compounds in Ebro river and industrial waste water. Identification was achieved by comparison of the UV spectra corresponding to the different peaks, acquired with a diode-array detector, with those in a spectral library.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02292977
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Polycyclic aromatic hydrocarbons in waste waters and sewage sludge: Extraction and clean-up for HPLC analysis with fluorescence detection (1996)
    Springer
    Chromatographia 43 (1996), S. 135-142 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Polycyclic aromatic hydrocarbons ; Waste waters ; Sewage sludge
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A modified solid-phase extraction technique using sonication of the adsorbent material instead of the elution normally applied has been compared with two conventional liquid-liquid extraction procedures for the determination of the 16 EPA PAHs in municipal waste waters by means of HPLC coupled with fluorescence detection. Liquid-liquid extraction with cyclohexane proved to be the most efficient and simplest procedure. Clean-up of the waste-water extracts was not considered necessary, because of the high chromatographic resolution of the column and the selectivity of the fluorescence detector. Different organic solvents were also compared for ultrasonic extraction of PAHs from sewage sludge. The best results were obtained by use of acetonitrile. Clean-up of sewage-sludge extracts was not found necessary for accurate quantification of the major PAH components with fluorescence detection. The precision of the whole analytical procedure from extraction to the final determination of PAHs was satisfactory for both waste-water and sewage-sludge samples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02292941
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Optimization of alkali-alkalkine earth cation separation on weak cation-exchangers (1996)
    Springer
    Chromatographia 43 (1996), S. 117-123 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ion-exchange chromatography ; Ion-exchange mechanism ; Optimization of alkali and alkaline earth separation ; Crown ether complexing reagents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The elution behavior of alkali and earth alkaline cations has been studied on a newly synthesized weak cationexchanger (WCX). Applying this stationary phase isocratic separation of these cations is possible. The dependence of retention on competing ion concentration is described via a simple model. The influence of crown ethers as well as organic eluent additives on selectivity and peak efficiency is demonstrated. With optimized separation such cations can be determined with detection limits of about 0.5 ppm using a conductivity detector without ion suppression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02292938
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Selectivity of dansyl amino acids in micellar liquid chromatography with an ion-exchange-induced stationary phase (1996)
    Springer
    Chromatographia 43 (1996), S. 143-148 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Micellar liquid chromatography ; Ion-exchange-induced stationary phase ; Dansyl amino acids (Dns-AAs) ; Fluorescence enhancement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention behavior of dansyl amino acids in micellar liquid chromatography has been examined by using ionexchange-induced stationary phases. Several parameters affected the retention of the analytes, including the type and concentration of micellar agent and modifier ion and the concentration of acetonitrile in the mobile phase. The order of elution of dansyl amino acids obtained with the micellar mobile phase was very different from that observed in conventional reversed-phase liquid chromatography. Fluorescence intensities of some dansyl amino acids were enhanced by the micellar mobile phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02292942
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    High-performance liquid chromatography of some estrogens on chemically bonded phases (1996)
    Springer
    Chromatographia 43 (1996), S. 551-556 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chemically bonded silica gel ; Mixed solvents ; Steroids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The chromatographic behaviour of 30 estradiol and estrone derivatives has been studied on diol, amino- and cyanopropyl silica gel stationary phases with non-aqueous mobile phases. The slopes of linear relationships between the logarithm of the retention factor and logarithm of the volume fractions of the polar components of the binary eluents have been calculated and are discussed in relation to the characteristics of the solute, eluent and stationary phase. An equation for testing the separation efficiency of stationary phases has been derived.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02293009
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Study on the relationship between retention behavior and molecular structure parameters of substituted benzene derivatives in RPLC (1996)
    Springer
    Chromatographia 42 (1996), S. 43-48 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Substituted benzenes ; Solubility parameter ; Substituent constant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A quantitative structure-retention model derived from the concept of hydrophobic substituent constant (π) and the total solubility parameter (δT) has been established. It has been used to predict successfully the retention behavior of a number of solutes on various columns in several different eluents. The experimental results indicate that the model can be employed for the prediction of retention of substituted benzenes in a large volume fraction range of mobile phase. In addition, the physical meaning of the sign and the influence of the coefficients of the model on the retention process had been discussed together with the dependence of these coefficients on the composition of mobile phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02271054
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    Effect of temperature on the mechanism of retention of fullerenes in liquid chromatography using various alkyl bonded stationary phases (1996)
    Springer
    Chromatographia 42 (1996), S. 56-62 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Fullerences ; Alkyl bonded silica phases ; Retention vs. column temperature ; CP-MAS NMR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The temperature-dependency of the separation of fullerenes in liquid chromatography (LC) has been examined using various alkyl bonded stationary phases. It has been found that a maximum retention temperature exists with long alkyl bonded stationary phases, whereas there is no similar effect with the newly synthesized alkyl bonded phases which have two phenyl groups at the base of the bonded phase. The interpretation of the retention behavior of fullerenes in the low temperature region on alkyl bonded stationary phases is discussed using information obtained by CP-MAS solid-state NMR spectroscopy and LC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02271056
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    LC-separation of derivatized DL-amino acids by aminopropylsilica-bonded Marfey's reagent and analog (1996)
    Springer
    Chromatographia 42 (1996), S. 683-689 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chiral stationary phase ; Enantionary phase ; Enantiomer separation ; Amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Two chiral stationary phases (CSP-1 and CSP-2)) were synthesized by covalent bonding of aminopropylsilica (APS) to (a) 1-fluoro-2,4-dinitrophenyl-5-L-alanine amide (Marfey's reagent), followed by end-capping of underivatized amino groups of APS with trifluoroacetic anhydride (CSP-1), and (b) by reaction of APS with 1-fluoro-2,4-dinitrophenyl-5-L-phenylalaninetert. butyl ester, followed by cleavage of the tert. butyl ester by trifluoroacetic acid and end-capping of underivatized amino groups of APS withn-butyryl chloride (CSP-2). Both CSPs were found to be suitable for the chiral resolution of 2,4-dinitrophenyl and 3,5-dinitrobenzoyl-DL-amino acid esters by liquid chromatography using mixtures ofn-hexane andiso-propanol as eluents. Racemic 2,2,2-trifluoro-1-(9-anthryl)ethanol was also resolved on CSP-2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02267702
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    Calcium phosphate hydroxyapatite and lead phosphate hydroxyapatite for separation by liquid chromatography (1996)
    Springer
    Chromatographia 42 (1996), S. 177-180 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Calcium and lead phosphate hydroxyapatite ; Globular proteins ; Colecalciferol (Vitamin D3) and related compounds ; Organophosphorus insecticides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A qualitative study using two new stationary phases (spherical aggregates of calcium phosphate hydroxy-apatite and lead phosphate hydroxyapatite) as adsorbents in high performance liquid chromatography has achieved the separation of: a standard mixture of globular proteins; colecalciferol and related compounds (produced by irradiation and heating of provitamin D3); and a mixture of organophosphorus insecticides used in agriculture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02269649
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Analysis of contact allergenic compounds in oxidizedd-limonene (1996)
    Springer
    Chromatographia 42 (1996), S. 199-205 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Negative ion CI mass spectrometry ; Oxidizedd-limonene ; Contact allergenic compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A detailed chemical analysis and quantification of oxygen-containing monoterpenes in auto-oxidizedd-limonene was performed. Some of these, e.g. the cis- and trans-isomers of limonene-2-hydroperoxide, have previously been shown to exhibit strong contact allergenic properties. GC-MS with chemical ionization in negative ion mode was shown to be a successful method for the identification and determination of the molecular weight of chemically unstable limonene hydroperoxides. An HPLC method for isolation of individual compounds in auto-oxidizedd-limonene is presented. Two different stationary phases were used in normal phase mode, cyanopropyl- and diamino-modified silica. The method described can be used for the isolation of individual contact allergens in sensitization experiment vehicles, such as petrolatum and olive oil. This makes it possible to study whether test compounds, such as hydroperoxides, are chemically stable during a sensitization experiment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02269653
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    Native and modified alumina, titania and zirconia in normal and reversed-phase high-performance liquid chromatography (1996)
    Springer
    Chromatographia 42 (1996), S. 217-222 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Stationary phases ; TiO2 ZrO2 AlO3 ; Separation of basic compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Chromatographic properties of silica, alumina, titania and zirconia have been investigated in normal phase mode in the separation of test mixtures of basic, neutral and acidic compounds. In contrast to silica the chromatographic behaviour revealed the basic properties of the alumina, titania and zirconia surfaces. Therefore, separation of basic compounds on these packings seems very promising. Lypophilic packings have been synthesized by modification of titania, zirconia and alumina with organosilanes and polymers and tested for the separation of basic compounds and proteins. High hydrolytic stability of the modified packings was observed during separations with strong alkali and acidic eluents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02269656
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    Determination of ampicillin in New Zealand white rabbit plasma using column switching technique and HPLC (1996)
    Springer
    Chromatographia 42 (1996), S. 223-226 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Column-switching technique ; Rabbit plasma ; Ampicillin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The purpose of this study was to develop a simple and fast analytical method for quantitation of ampicillin in rabbit plasma, suitable for analysis of large numbers of samples collected from experimental animals. The concentration of ampicillin in rabbit plasma was determined utilizing ion-pair reverse-phase high performance liquid chromatography (HPLC) with UV detection and a column switching technique. Plasma samples were treated with a perchloric acid solution to precipitate proteins and centrifuged to pellet the precipitated proteins. Cephalexin was used as an internal standard. The C18 precolumn was placed in the injector loop of the Rheodyne injector. Samples were injected with the injector in the load position and the precolumn was washed free from interfering compounds. When the injector was switched to the inject position, the mobile phase was passed through the precolumn taking relatively pure compounds onto the analytical column. The limit of quantitation was established to be 400 ng mL−1 of plasma. The standard curves were linear over the range of ampicillin concentrations assayed, 400 to 10,000 ng mL−1 of rabbit plasma, and had a mean regression coefficient of 0.9962 (±0.0043). Intra-day variability was determined using six replicates of controls (low and high) analyzed on a single assay. The percent of relative accuracy for low and high controls were 5.67 and 1.12, respectively. Inter-day variability was determined over a four day period analyzing replicates of each control. The percent of relative accuracy for low and high controls were 4.33 and 1.63, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02269657
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    A chromatographic comparison of the pore structure of zirconia high performance liquid chromatographic materials made by the polymerization induced colloidal aggregation and the Oil Emulsion methods (1996)
    Springer
    Chromatographia 42 (1996), S. 273-282 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Size exclusion chromatography ; Pore structure ; Nitrogen sorptometry ; Zirconium oxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The pore structures of zirconium oxide particles prepared by two different methods (PICA and Oil Emulsion processes) are compared. Nitrogen sorptometry and size exclusion chromatography are used to characterize the two different types of particles. Significant and unexpected differences were found in the accessible pore volumes and the bed packing densities of the two materials. The PICA material was found to have a higher totally included and totally excluded volume than would be normally expected. The chromatographic method provides results which are more useful for the application of these materials to separation sciences.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02290309
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    HPLC study of the binding of sulfinpyrazone to serum albumin (1996)
    Springer
    Chromatographia 42 (1996), S. 401-404 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Hummel Dreyer method ; Sulfinpyrazone ; Bovine serum albumin ; Scatchard-Rosenthal plot
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Hummel-Dreyer method was used to study the binding of sulfinpyrazone to bovine serum albumin. The technique involves our newly developed internal calibration method with the elution pattern consisting of two positive peaks and with the integrator to evaluate the area of second peak. From the area of the second peak the numerical value ofL b (the amount of drug bound to protein) was calculated. Sctachard-Rosenthal plot was used to estimate the binding parametersn i (the number of binding sites) andk i (the binding constants). The results are compared with those obtained by equilibrium dialysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02272130
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    Indirect liquid chromatographic determination of malathion based on copper(II) dimethyldithiophosphate complex formation (1996)
    Springer
    Chromatographia 42 (1996), S. 680-682 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Cu(II) dimethyldithiophosphate complex ; Malathion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A high-performance liquid chromatographic method has been developed for the quantitative determination of the organophosphorus pesticide malathion. The method is based on alkaline hydrolysis of malathion to dimthyldithiophosphate (DDTP) which is complexed with copper(II) and extracted in chlorofrom. The complex is injected onto a Hypersil ODS or Licrosorb sicolumn and eluted with acetonitrile:methanol:water (80∶10∶10 v:v:v) or chloroform. Detection is at 245 or 260 nm. A linear calibration curve was obtained for 24–240 μg ml−1 DDTP and a detection limit of 2.4–4.8 ng DDTP per injection. The method was applied to the analysis of malathion in commerical products after spraying on leaves. Extrction efficiency of malathion from leaves in acetone-water was also evlauted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02267701
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    Gas and liquid chromatography and enzyme linked immuno sorbent assay in pesticide monitoring of surface water from the western mediterranean (Comunidad Valenciana, Spain) (1996)
    Springer
    Chromatographia 42 (1996), S. 151-158 
    Details
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Column liquid chromatography ; Pesticide residues ; Surface water analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A monitoring programme based on gas chromatography (NPD, ECD) using MSD for confirmatory purposes and coupled-column liquid chromatography was applied to the analysis of pesticide residues in surface water from a predominantly agricultural area of Spain (Comunidad Valenciana). Samples analysed by means of enzyme-linked immunosorbent assay gave similar results to those obtained by GC (MSD) for the determination of total triazines. The test employed had the advantages of a simple test procedure, short analysis time and high confirmatory value. Nevertheless, the multiresidue character, accuracy and unequivocal identification of individual pesticide residues of GC (MSD) make this technique the most appropriate for environmental monitoring programmes. In this monitoring programme about 200 samples were analysed between 1993–1994. 27 different pesticides were detected in 91 of these samples. The pesticides more frequently detected were dimethoate, methidathion, endosulfan A and B, endosulfan sulphate and pirimicarb. The highest concentrations found were 39.9 μg L−1 of dimethoate, 10.6 of pirimicarb and 10.6 of methidathion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02269645
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    Supported liquid membrane work-up in combination with liquid chromatography and electrochemical detection for the determination of chlorinated phenols in natural water samples (1996)
    Springer
    Chromatographia 42 (1996), S. 165-170 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Liquid membrane extraction ; Chlorinated phenols ; Natural water samples
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A sample preparation method has been developed for the determination of chlorinated phenols in water. The method is based on a supported liquid membrane extraction system connected on-line to liquid chromatography with electrochemical detection. The supported liquid membrane technique utilizes a porous PTFE membrane. The membrane is impregnated with an organic solvent which forms a barrier between two aqueous phases and enables selective extraction. The technique can easily be coupled in a flow system. In this investigation five chlorinated phenols (1–5 chlorine atoms) were extracted from natural water samples. Extraction for 30 minutes resulted in detection limits of approximately 25 ng L−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02269647
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    Sample size and retention values in gradient liquid chromatography of synthetic polymers (1996)
    Springer
    Chromatographia 42 (1996), S. 185-190 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gradient elution of synthetic polymers ; Polystyrene and various styrene copolymers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Retention times in gradient liquid chromatography of synthetic polymers are often dependent on sample size. They increase with column load if the separation mechanism is governed by a solution process but decrease with increasing load if the mechanism is governed by adsorption. Since retention times independent of sample size are a prerequisite for peak identification as well as for the correct measurement of elution bands of samples with a broad distribution, measures to counteract sample-size effects deserve attention. Usually both solubility and adsorption are effective in gradient liquid chromatography of synthetic polymers. An appropriate balance of both effects is suitable for diminishing the influence of sample size on retention time of synthetic polymers. Ternary gradients allowing independent control of solubility and adsorption are promising.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02269651
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Supercritical fluid extraction of carbamate pesticides from soils and cereals (1996)
    Springer
    Chromatographia 42 (1996), S. 206-212 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Supercritical fluid extraction ; Carbamate pesticides ; Soils ; Cereal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method for the supercritical fluid extraction of carbamate pesticides (propoxur, aminocarb, carbaryl and methiocarb) from soil and cereal samples using CO2 is proposed. Extractions were at 378 bar and 54 °C. Analytes were determined in the extracts by HPLC with fluorescence detection after post-column derivatization. Recoveries from spiked soil ranged between 39.6 and 91.7%, depending on analyte and soil components. Lowest recoveries were from sandy soils. Aminocarb could not be recovered from any soil using CO2. Recovery of aminocarb from diatomaceous earth was improved by adding methanol to the extraction cell prior to SFE, but the effect was not observed in soil samples. Recoveries for propoxur and aminocarb from spiked wheat were about 75%, and only between 30–50% for aminocarb from corn and oats, and carbaryl from wheat. Fat was coextracted using CO2 and retained in the trap together with the analytes, however, appropriate rinsing solvent allowed on-line clean-up of the extract.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02269654
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    H-point standard additions method for resolution of overlapped chromatographic peaks with a conventional fluorescence detector. Determination of phenol and cresols in waters (1996)
    Springer
    Chromatographia 42 (1996), S. 283-289 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Peak overlap ; Fluorescence detection ; H-Point standard additions method ; Water analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The H-Point Standard Additions Method (HPSAM) is proposed in order to resolve overlapping peaks in liquid chromatography by using a conventional fluorescence detector. The method uses as analytical signals the heights or the areas obtained at two previously selected emission wavelengths, and good results are obtained for highly overlapping peaks with highly overlapping fluorescence spectra. The principal benefits of the method are the ease of finding the required wavelengths, its insensitivity to changes in the retention time of the peak from one injection to another, and the possibility of using it in highly or only partially overlapping peaks. We have applied the method to the determination of phenol and cresols in water, resolving by the proposed method the overlapping peaks ofm- andp-cresol.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02290310
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    HPLC evaluation of mono-ol, butylphenyl and perfluorinated columns prepared via olefin hydrosilation on a silica hydride intermediate (1996)
    Springer
    Chromatographia 43 (1996), S. 10-16 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Synthesis of new liquid phases ; Evaluation of new phases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Three columns, mono-ol, butylphenyl and perfluorinated synthesized through the reaction of an olefin with a silica hydride intermediate, are evaluated for the separation of various model compounds. Two of the columns, mono-ol and perfluorinated, can operate in both the normal phase and reversed phase modes. Some effects of the hydride surface are detected, particularly for the perfluorinated phase. A four-component steroid mixture is tested on both the mono-ol and perfluorinated phases in the normal mode.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02272815
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    Liquid chromatographic determination of nitroaromatics in water following solid phase extraction, pre-column reduction and derivatization (1996)
    Springer
    Chromatographia 43 (1996), S. 25-30 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Nitroaromatics ; Solid phase extraction ; Reduction and derivatization ; Fluorescence detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A selective and sensitive method for determination of nitroaromatics is described. The analytes were reduced to corresponding primary amines with iron powder and then derivatized with fluram in citrate buffer to form pyrrolinones. The highly fluorescent pyrrolinones were isolated and preconcentrated by octadecylsilane solid phase extraction cartridge followed by reversed-phase, high-performance liquid chromatographic analysis. Detection was at 395–495 nm. Various aspects such as the reduction process, derivatization, solid phase extraction and chromatographic separation were optimized. Analysis time was relatively short due to a special design for successive reduction and preconcentration. Limits of detection for 3-nitrophenol, nitrobenzene, 4 and 2-nitrotoluene were less than 60, 12, 60 and 280 ng L−1 respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02272817
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    An improved method for determination of the activity of β-galactosidase in yoghurt by high-performance liquid chromatography (1996)
    Springer
    Chromatographia 43 (1996), S. 85-88 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Yoghurt ; β-Galactosidase activity ; Glucose ; Galactose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A new method has been developed for the HPLC determination of the activity of lactase from the microorganisms in yoghurt. The method is based upon the ability of β-galactosidase to hydrolyze lactose bonds in glucose and galactose. To determine such activity in yoghurt, 1 mL of yoghurt was diluted 1∶10 with 0.1 M phosphate buffer (pH 7) containing 2 % (w/v) lactose and 5 mM dithioerythritol as reducing agent; the mixture was the incubated and injected into the HPLC. Lactase activity remained high as long as the number of viable microorganisms did not fall below the minimum CFU·mL−1 (107). This method is more repeatable than conventional colorimetric determination, and may also be automated for routine analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02272828
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    Determination of tetramethylthiuram disulfide (Thiram) in river water by high-performance liquid chromatography: Micellar versus conventional reversed phase chromatography (1996)
    Springer
    Chromatographia 43 (1996), S. 607-611 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Micellar vs. reversed phase separation ; Thiram in river water ; Dithiocarbamate fungicides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary After a comparative study of conventional reversed phase and micellar liquid chromatography a method is described for the determination of the fungicide thiram in river water based on the use of micelles of CTAB. The method involves the extraction/concentration of thiram with a C18 cartridge followed by separation on a C18 reversed-phase column with a mobile phase of 20% (v/v) acetonitrile/0.01 M CTAB in phosphate buffer (pH-6.3), and detection at 254 nm. The method allows the determination of thiram in the presence of other water-soluble dithiocarbamate fungicides (nabam, ziram and ferbam) with a limit of detection of 36 pg mL−1 for a typical 20-fold preconcentration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02292975
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Thin-layer and column chromatography of sulfonamides on aminopropyl silica gel (1996)
    Springer
    Chromatographia 43 (1996), S. 654-658 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Thin-layer chromatography ; Ion-pairing ; Sulfonamides ; NH2-Modified stationary phase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Thin-layer and column high-performance liquid chromatography based on amino propyl-modified silica gel using aqueous and non-aqueous mobile phases containing organic modifier and cationic or anionic ion-pairing reagents were used for the determination ofR F andk values of some sulfonamides. The influence of the different organic modifiers and ion-pairing reagents on retention has been compared.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02292983
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    Application of a new non-porous stationary phase (Kovasil-H) for the fast separation of peptides by HPLC (1996)
    Springer
    Chromatographia 42 (1996), S. 595-598 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Non-porous, reversed phase packing ; Fast peptide separation ; Peptide mapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Kovasil-H, a new 1.5 μm, non-porous, silica-based, reversed phase packing was investigated for the peptide mapping of Bovin Serum Albumin (BSA) and Cytochrome c tryptic digests and for the quality control of trypsin. Using short columns (33–66 mm) and high temperature, very short analysis times and high sensitivities were attained. No special modification of commonly used liquid chromatographs are necessary for the application of this method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02290299
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    Chromatographic determination of caffeine in pharmaceutical formulations using micellar mobile phases (1996)
    Springer
    Chromatographia 43 (1996), S. 149-152 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Caffeine ; Pharmaceutical formulations ; Micellar liquid chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An HPLC procedure is described for the determination of caffeine in pharmaceutical preparations. A Spherisorb octadecylsilane ODS-2 C18 analytical column and spectrophotometric detection at 273 nm were used. The chromatographic behaviour of caffeine with different micellar eluents containing sodium dodecyl sulphate (SDS) is described. The determination of caffeine in pharmaceutical preparations was performed by use of a mobile phase containing 0.05 M sodium dodecylsulphate (SDS) and 1.5% propanol at pH7. At a 6.0 μg mL−1 concentration level the peak area and peak height repeatability were 2.6 and 2.4%, respectively. The application of the proposed method to the analysis of five pharmaceutical formulations, using peak heights as the dependent variable, gave recoveries between 85 and 104% of the values declared by the manufacturers. The proposed procedure for the determination of caffeine is rapid (15 min per sample), reliable and free from interferences.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02292943
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    Improved detection of leucovorin in mixed folates and antifolates by reversed-phase liquid chromatography and on-line post-column UV irridiation (1996)
    Springer
    Chromatographia 43 (1996), S. 327-330 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Leucovorin, methotrexate ; On-line, post-column UV irradiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An improved, reversed-phase, high-performance liquid chromatography (HPLC) method with dual UV-fluorescence detection for simultaneous determination of the antifolate methotrexate, the folate leucovorin and their two main metabolites 7-hydroxymethotrexate and 5-methyltetrahydrofolate, respectively is presented. The fluorescence intensity of leucovorin could be significantly increased by on-line, post-column irradiation with UV at 254 nm thus lowering the limit of detection for leucovorin to 0.2 ng absolute at a signal-to-noise ratio 3∶1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02271004
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    High performance liquid chromatography of disaccharides on a porous graphitic carbon column applying post-column derivatization with benzamidine (1996)
    Springer
    Chromatographia 43 (1996), S. 254-260 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Carbohydrates ; Anomer separations ; Post-column derivatization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A sensitive post-column fluoresence method based on the reaction of reducing sugars with a fluorigenic reagent (benzamidine) under alkaline conditions and elevated temperature is described. Optimum reaction conditions suitable for the detection of fluorescent reaction products have been investigated. A porous graphitized carbon column (shandon Hypercarb) was employed as the chromatographic solid phase and elution was isocratic by an aqueous acetonitrile mixture. A special problem in sugar analysis is the tendendy of anomer formation giving doublet peaks. This tendency varies largely among the different sugars, and systematic studies on conditions that eliminate this problem were performed. Efficient and selective separations of a series of disaccharides were obtained using high temperatures and a low concentration of acetonitrile in the mobile phase. The detection limits (S/N=3) with an injection volume of 20 μL ranged from 10–60 picomoles. Linear calibration graphs were obtained in the 2–20 μM concentration range (r 2〉0.99). A relative standard deviation between 1–3% (n=6) demonstrated good precision of the developed system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02270990
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    Amino acid analysis by derivatization with chromogenic 4-phenylazobenzyloxycarbonyl chloride (PAZ-Cl): Comparison of reversed-phases (1996)
    Springer
    Chromatographia 43 (1996), S. 275-278 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chromogenic reagent ; Chloroformate ; Pre-column derivatization ; Amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The chromogenic reagent 4-phenylazobenzyloxycarbonyl chloride (PAZ-Cl) was used for the automated pre-column derivatization of amino acids (AAs) at ambient temperature followed by liquid chromatographic separation of the derivatives formed. Since in previous investigations it was realised that the selectivity of a C-18 stationary phase decreased after 40 injections of PAZ-AAs the suitability of 12 reversedphases distinguished by silica modification, carbon content, and particle characteristics was tested. Among these columns only a polymer-coated C-18 stationary phase furnished satisfactory repeatability of retention times for 250 analyses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02270994
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    Identification of the [(bpy)2Ru(Im)(H2O)]2+ complex as an reaction intermediate by reversed-phase high-performance liquid chromatography (1996)
    Springer
    Chromatographia 43 (1996), S. 322-326 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ruthenium diimine complexes ; Inorganic synthesis ; Kinetics monitoring
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The synthesis of the complex [(bpy)2Ru(Im)2]2+ (bpy=2,2′-bipyridine; Im=imidazole) has been monitored by reversed-phase HPLC. The analytical results obtained during the reaction have shown that it is feasible to identify and isolate the [(bpy)2RuIm(H2O)]2+ complex as a reaction intermediate. The optimization of the synthetic procedures for these two species has been established and the compounds have been obtained in high purity. The use of HPLC has enabled complete analytical control of the synthesis of the [(bpy)2RuL2]2+ class of compounds, enabling the identification of reaction intermediates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02271003
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    Simultaneous determination of triprolidine, pseudoephedrine, paracetamol and dextromethorphan by HPLC (1996)
    Springer
    Chromatographia 43 (1996), S. 496-500 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Pharmaceutical formulations ; Triprolidine ; Pseudoephedrine ; Paracetamol ; Dextromethorphan
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple, rapid and specific HPLC method has been developed for the determination of triprolidine, pseudoephedrine, paracetamol and dextromethorphan, in combination, in different pharmaceutical dosage forms, using a reversed-phase C18 column, gradient elution, and UV detection at 254 and 280 nm. No preliminary extraction procedure is required for liquid formulations and a very simple extraction procedure is required for tablets and creams. The recovery of the drugs ranged from 96.0 to 98.7%. The assay results obtained for eight commercially available formulations were in agreement with the amounts declared. The linearity and precision of the method have been assessed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02293000
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Thermal degradation of single 7-cholesteryl acetate hydroperoxide (1996)
    Springer
    Chromatographia 42 (1996), S. 29-33 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gas chromatography-mass spectrometry ; 7-Cholesteryl acetate hydroperoxides (CAHPs) ; Thermal degradation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The thermal degradation products of the 7α- and 7β-cholesteryl 3β-acetate hydroperoxides obtained by thermal oxidation of cholesteryl 3β-acetate are reported and discussed. The hydroperoxides were degraded in both the vapour and condensed phases. The main components identified were 7-ketocholesteryl 3β-acetate, 7α- and 7β-hydroxycholesteryl 3β-acetates and the products generated from the loss of the hydroperoxide group and/or of acetic acid. Remarkable is the finding of the epoxy-hydroxy derivatives of cholesteryl acetate among the degradation products.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02271051
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    Simultaneous assay of copper iron and uranium in phosphate media by ion-pair liquid chromatography (1996)
    Springer
    Chromatographia 42 (1996), S. 34-38 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; On-column ion complexation ; Simultaneous metal ion analysis ; Analysis of standard references
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Ion-pair, high-performance liquid chromatography has been used for the simultaneous separation of Cu(II), Fe(II) and U(VI) as their proposed, anionic [M(H2PO4)3]− and neutral complexes with tetrabutylammonium (TBA)+ as ion-pairing reagent. The concentration effect of (TBA)+, organic modifier and pH of the eluent on the separation was investigated. The UV detector response at various wavelengths has been optimized. Detection limits of Cu(II), Fe(II) and U(VI) were 12, 6 and 12 ng respectively. The method is compared with atomic absorption spectroscopy spectrophotometry for determination of metal ions in synthetic mixtures as well as in Standard Reference Materials (SRMs).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02271052
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Siliceous materials with the surface polymer layer composed of dextran-polyimine mixture as column packings for liquid chromatography (1996)
    Springer
    Chromatographia 42 (1996), S. 49-55 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Dextran-polyimine stationary phases ; Affinity ligands ; Ligand-exchange chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Forming a polymer layer on the surface of siliceous materials is one of the methods for protecting the silica skeleton from dissolution in alkaline mobile phases as well as eliminating the negative influence of silanol groups on separated molecules e.g. proteins. Polysaccharides, especially their derivatives bearing amine groups, can play the role of the surface layer. This paper discusses the possibilities of preparing such a layer by cross-linking a dextran-polyimine mixture (rather than the traditionally used DEAE-dextran) deposited on the surface of the solid material. The results presented prove the utility of synthesized materials as supports for affinity ligands in high performance affinity chromatography or as supports for complexed metal ions in ligand-exchange chromatography. The properties of the sorbents with a polymer layer can be changed both by the composition of the cross-linked mixture and by chemical modification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02271055
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    Cross validation of capillary electrophoresis and high-performance liquid chromatography for cefotaxime and related impurities (1996)
    Springer
    Chromatographia 42 (1996), S. 159-164 
    Details
    ISSN: 1612-1112
    Keywords: Capillary electrophoresis ; Column liquid chromatography ; Cefotaxime impurities ; Cross validation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A micellar electrokinetic chromatography method is presented which permits separation of cefotaxime and its major related impurities. Separation was carried out at 15 kV, using 30 mM sodium dihydrogen phosphate adjusted to pH 7.2 with 5 M NaOH and which contained 165 mM sodium dodecylsulfate as electrolyte. Results obtained by capillary electrophoresis were in good agreement with those of high-performance liquid chromatography with respect to the level of the major known impurities, total impurity content and cefotaxime purity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02269646
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    Detection of cow's milk in ewe's or goat's milk by HPLC (1996)
    Springer
    Chromatographia 42 (1996), S. 181-184 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ewe's milk ; Whey proteins ; Goat's milk
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary High-pressure liquid chromatography (HPLC) was used to detect added cows' milk in goat and ewe's milk. Analysis of the whey proteins enabled detection of mixtures in proportions of less than 1%. The method does not distinguish between goat and ewe's milk.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02269650
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    Chracterization of polyaniline using chromatographic studies (1996)
    Springer
    Chromatographia 42 (1996), S. 191-198 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Polymer-coated silica phase ; Polyaniline ; PAHs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The use of polyaniline as a chromatographic stationary phase has been examined. In the course of this work the column packing material was prepared by coating silica particles with polyaniline chloride. The aniline monomer was polymerised directly on the surface of the silica particles using a chemical method and was characterised using elemental analysis. A series of standard test compounds were employed for chromatographic characterization. The studies revealed information on the practical utility as well as the molecular interactions that took place on the stationary phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02269652
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    Isocratic high-performance liquid chromatographic determination of plasma adenosine (1996)
    Springer
    Chromatographia 42 (1996), S. 318-322 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Adenosine in blood ; Isocratic elution ; Stop-solution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Due to manifold physiological and cardioprotective actions of adenosine, the demand for a simple but accurate method to determine its concentration in plasma is increasing. The aim of this study was firstly to develop a simple isocratic method instead of the gradient elution or peak-shifting techniques used earlier and secondly to check conflicting data on the composition of “stop-solution”, added to the sample in order to prevent changes in adenosine concentration. Isocratic elution improved signal to noise ratio and concentrations of 100 μmol L−1 dipyridamole and 2.5 μmol L−1 erythro-9(2-hydroxy-3-nonyl)adenine in the blood sample effectively prevented both adenosine formation and degradation, even without the use of a 5′-ecto-nucleotidase inhibitor. Lowering the concentration of dipyridamole to 25 μmol L−1 caused more than a tenfold increase of adenosine concentration in two out of five cases and even 100 μmol L−1 dipyridamole alone is not sufficient to inhibit adenosine deaminase in blood samples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02290317
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    Comparison and quantification of chromatographic retention mechanisms on three stationary phases using structure-retention relationships (1996)
    Springer
    Chromatographia 42 (1996), S. 389-395 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Structure-retention relationship ; Polar modifiers ; Molecular modelling ; Retention mechanism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The mechanism of retention in HPLC using a non-polar solvent with a very low content of various polar modifiers as mobile phase and three stationary phases is studied. The results of preceding work are generalised to the role of each polar modifier. This allows quantification of the interaction between stationary phases and polar modifier. Moreover, by the introduction of physicochemical descriptors of eluents it is possible to obtain for each stationary phase a simple equation correlating retention of solutes to calculated descriptors of solutes and eluents. The mechanism of retention is discussed with these new general equations. The main qualitative result is proof of a direct link between the polar modifier and polar groups of the stationary phases, This link plays the major role in differences of retention.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02272128
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    Separation and characterisation of hop bitter acids by HPLC-1H NMR coupling (1996)
    Springer
    Chromatographia 42 (1996), S. 499-505 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Hop bitter acids ; Supercritical fluid extraction ; On-line-1H NMR coupling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A supercritical carbon dioxide hop extract has been analysed using on-line coupling of high performance liquid chromatography (HPLC) with1H nuclear magnetic resonance (NMR) spectroscopy. For the first time high quality NMR spectra of the six major hop bitter acids were recorded by employing the stopped-flow detection mode. The resolution of the spectra obtained is similar to that of conventionally recorded spectra. All data are in agreement with the known structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02290283
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    A comparative study of the metal selective properties of chelating dye impregnated resins for the ion chromatographic separation of trace metals (1996)
    Springer
    Chromatographia 42 (1996), S. 528-538 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chelation ion chromatography ; Dye impregnated resins ; Trace metals in seawater
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary High-performance chelation ion chromatography (HPCIC) involving the use of chelating dye impregnated resins has been investigated for its ability to preconcentrate and separate a range of metals in a variety of complex samples. The parameters involved in the production of dye impregnated chelating columns have been identified and investigated. A number of selected chelating dyes have been impregnated into high-performance substrates, producing a range of chelating columns, exhibiting unique retention characteristics, dependent upon the nature of the impregnated chelating ligand. These columns have been classified in terms of retention characteristics, separation efficiency, dye loading and column capacity. A brief application of the above technique to the determination of Al (III) in seawater is illustrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02290287
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    Synthesis and chromatographic properties of HPLC chiral stationary phases based upon β-cyclodextrins (1996)
    Springer
    Chromatographia 42 (1996), S. 583-590 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chiral stationary phases ; Bonded cyclodextrins ; Reversed and normal mode separations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary β-cyclodextrin chiral stationary phases (CD-CSP) having different spacer lengths have been prepared and evaluated (retention, selectivity, resolution) for the liquid chromatographic separation of several series of enantiomers. The influence on the separations of the spacer length is discussed. The CD-CSPs were evaluated under normal and reversed mode conditions and the results compared with those from two commercial stationary phases containing β-cyclodextrin Chiradex and Cyclobond I.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02290296
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    Bioactivity screening by chromatography-bioluminescence coupling (1996)
    Springer
    Chromatographia 43 (1996), S. 5-9 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Thin-layer chromatography ; Bioactivity detection ; Bioluminescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Because luminescent microorganisms change their light emission in the presence of bioactive substances, they provide an effective way of monitoring toxicity. Here we report the direct coupling of bioluminescence to chromatography which is capable of detecting single toxic components in complex mixtures. Two approaches were investigated, utilizing thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). The TLC-bioluminescence imaging technique was developed into a versatile and rugged method and proved to be superior to the HPLC-based design. Employing genetically engineered luminescent bacteria gives customized selectivity of bioactivity detection. The combination of analytical separation technology with the biospecific sensing ability of living cells provides a novel screening tool for targeting bioactive components in complex samples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02272814
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    HPLC determination of rhodamine B (C.I. 45170) in cosmetic products (1996)
    Springer
    Chromatographia 43 (1996), S. 76-78 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Rhodamine B in cosmetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method is proposed for the extraction, separation, identification and quantitative measurement of rhodamine B in cosmetics samples The colour is extracted with a solution of orthophosphoric acid in either water or DMF (depending on the type of cosmetic) adsorbed on a polyamide column, and then eluted with water and methanol. Further clean-up of the extract is performed by means of a Bond Elut C-18 cartridge, from which rhodamine B is eluted with methanol-water (8∶2). The final eluate is examined by HPLC. Chromatography is performed on a C-18 column with a gradient elution from 50∶50 to 70∶30 of acetonitrile-water, containing 0.1 M sodium perchlorate, in 15 min. A diodearray detector enables peak purity analysis. The method gives recovery values of approximately 90%, or better, and the reproducibility is within 4%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02272825
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    Estimation of the pK a of the amine groups of benzhydrylamine resin and its lysyl derivative by measurement of swelling (1996)
    Springer
    Chromatographia 43 (1996), S. 82-84 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Anion-exchange chromatography ; Benzhydrylamine resin ; pK a
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary For better evaluation of the potential of benzhydrylamine resin (BHAR), used as a solid support for peptide synthesis, as a novel anion-exchange resin, the pK a of its amine group was estimated by microscopic measurement of the sizes of the dry and swollen beads. Using the volume of the bead occupied by the solvent (as a percentage) as the swelling parameter, a plot of the degree of swelling of BHAR loaded with 2.4 mmol g−1 amine groups against the pH of the medium produced a decreasing sigmoidal-type curve with increasing pH. By considering the point of inflection of the curve, a pK a value of approximately 7.5 was estimated for the amine group of the BHAR. The same approach was also applied to the lysyl derivative of the BHAR (Lys-BHAR) and pK a values around 6.5 and 10.0 were obtained for the α and ε amine groups, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02272827
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    Determination of nitrophenols, nitrobenzoic acids and polar explosives by HPLC-diode array detection in ground water samples of former ammunition plants (1996)
    Springer
    Chromatographia 43 (1996), S. 612-618 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Diode array detection ; Explosives residues ; Nitro-compounds ; Ground water ; Ammunition waste
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An HPLC method with diode array detection for the determination of acidic aromatic nitro compounds (in particular nitrophenols and nitrobenzoic acids) in ground water around former ammunition plants is presented. The use of an isocratic mobile phase, buffered to a pH of 2.30 on a reversed phase column, allows the separation of several nitrophenols and nitrobenzoic acids, some of which are known as phototransformation products of 2,4,6-trinitrotoluene (TNT). In a ground water sample from the former ammunition site at Elsnig (Saxony, Germany) 2,4- and 3,5-dinitrophenol (18), picric acid (8) and 2,4-dinitrobenzoic acid (3) were identified in addition to a variety of explosives determined previously. The presence of these compounds was corroborated by a diode-array (DAD)-library search.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02292976
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    Hexamethyldisiloxane as a mobile phase component for normal phase liquid chromatography (1996)
    Springer
    Chromatographia 43 (1996), S. 647-653 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Hexamethyldisiloxane ; Mobile phase component ; Silica column
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Hexamethyldisiloxane (HMDX) has been evaluated as a modifier solvent for the normal phase separation of substituted naphthalene componds as well as aromatics such as nitrobenzene, acetophenone, benzonitrile, and aniline. It is found to be a weaker eluting solvent than n-butyl ether and other commonly used normal phase solvents filling a niche in the eluotropic series. HMDX exhibited an unusual retention factor (k′) profile as a function of mobile phase composition in hexane. In a range from 0 to 40 %, thek′ values remained quite constant with increasing HMDX composition. As the concentration of HMDX progressed to 100 %, thek′ values actually increased in a generally linear fashion. This trend ink′ is due to longer solute retention not just a change in the retention time of the unretained component. Although slight silanization of the silica column may occur with initial use of HMDX, retention of these analytes on a commerical C-1 silica column is much lower with no positivek′ slope with increasing HMDX. The chromatographic data provide evidence that HMDX is likely adsorbed to the silica surface and a solute partitioning mechanism may be operative.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02292982
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    Identification and determination of fumonisin FB1 and FB2 in corn and corn products by high-performance liquid chromatography-electrospray-ionization tandem mass spectrometry (HPLC-ESI-MS-MS) (1996)
    Springer
    Chromatographia 43 (1996), S. 124-128 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Tandem mass spectrometry ; Fumonisin in corn products ; Electrospray-ionization (ESI) ; Selected rection monitoring (SRM)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A new method has been developed for qualitative and quantitative analysis of fumonisin FB1 and FB2 in corn and corn products. After extractive sample preparation followed by solid phase extraction using a strong anionexchanger, highest selectivity and sensitivity was achieved by high-performance liquid chromatography-electrospray-ionization, tandem mass spectrometry (HPLC-ESI-MS-MS) analysis combined with selected reaction monitoring (SRM). With deuterated fumonisin FB1-d6 as internal standard the routine quantitation limit for FB1 was set at 400 pg (0.8 ng g−1 sample) with a signal-to-noise ratio of 10∶1. Almost all corn grit and corn meal samples under study were found to be contaminated with fumonisin FB1 and FB2 in concentrations ranging from 1 to 200 ng g−1. Lower fumonisin levels were found in cornflakes, popcorn and baby food, while no fumonisins were detected in canned sweet corn.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02292939
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    HPLC determination of pesticides in green bean samples after SPE clean-up (1996)
    Springer
    Chromatographia 43 (1996), S. 265-270 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Diode array detection ; Solid-phase extraction (SPE) ; Pesticide analysis ; Multiresidue methods ; Green bean samples
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A reversed-phase high performance liquid chromatographic (HPLC) method with an acetonitrile-methanol-water mobile phase gradient and photodiode-array detection (DAD) is described for simultaneous determination of 21 pesticides, frequently used in agriculture, of different types, namely organophosphorus, organochlorine,N-methylcarbamates, triazines and phenylureas in vegetable samples. The pesticides were extracted with acetone and then partitioned from the vegetable sample with dichloromethane. Sample clean-up was accomplished by solid-phase extraction (SPE) using both C18 and florisil SPE columns. Average recoveries from green beans ranged from 70.0 to 110.1%. Detection limits of less than 0.1 mg kg−1 were obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02270992
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    Determination of acidic chlorinated pesticides in water: Comparison of official EPA method 515.1 and liquid-solid extraction HPLC/UV and HPLC/PBMS analyses (1996)
    Springer
    Chromatographia 43 (1996), S. 279-284 
    Details
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Column liquid chromatography ; ECD, UV and MS detection ; EPA Method 515.1 ; Chlorinated acidic pesticides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A comparison of the official EPA method 515.1 for determination of chlorinated acidic pesticides and a modification of it is illustrated. Extraction of the analytes from water and their determination and quantitation is by gas chromatography-electron capture detection (GC-ECD), liquid chromatography-UV detection and liquid chromatography-particle beam mass spectrometry. Although HPLC-PBMS was found to be less sensitive than the GC-ECD method, it was, nevertheless, more sensitive than HPLC-UV. The modified method is simpler, quicker and allows more accurate determination of pesticides in aqueous samples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02270995
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    Sensitive determination of amino acids in kelp by reversed phase high performance liquid chromatography with precolumn derivatization using phenylisothiocyanate (1996)
    Springer
    Chromatographia 43 (1996), S. 309-312 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Kelp ; Microwave hydrolysis ; precolumn derivatization ; Phenylisothiocyanate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A reversed phase high performance liquid chromatographic (RP-HPLC) method for the analysis of amino acids in kelp, using precolumn derivatization, is described. Phenylisothiocyanate (PITC) was used as the reagent for derivatization. The kelp samples were prepared by microwave hydrolysis in only 5 min; seventeen PTC amino acids were separated after hydrolysis and derivatization within 12 min. The coefficients of variation were 〉1.94 and the correlation coefficients for concentration versus response were 〉0.999 for all derivatives. The ratio of branched amino acid (BAA) to aromatic amino acid (AAA) was also studied. The method has the advantage of shorter hydrolysis and analysis times with optimum separation. In addition, it gives high repeatability of retention times and peak areas for all the amino acids present.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02271001
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    Retention on Diol column—A case study (1996)
    Springer
    Chromatographia 43 (1996), S. 436-438 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Diol columns ; Optimisation ; Ephedrine ; Synopen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The effect of simultaneous variation of buffer pH, molarity and organic modifier concentration when Diol stationary phase is used was experimentally studied. An equation has been derived for the retention time in the interpolation region of ephedrine and synopen—principal active components in an antihistamine formulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02271026
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    Simultaneous separation of inorganic anions and cations using binary eluent by ion chromatography with indirect photometric detection (1996)
    Springer
    Chromatographia 43 (1996), S. 473-476 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ion chromatography ; Indirect detection ; Binary eluent
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Inorganic cations and anions were separated simultaneously using sodium sulfosalicylic-EDTA binary eluent on a strong basic anion-exchange column. The effects of eluent pH, concentration and complexing effect of EDTA on retention behaviour of the ions were studied. The results showed that the larger the cation, the longer the retention time — except for Ca2+.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02292996
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    High-performance liquid chromatographic characterization of rhenium bipyridine complexes with phosphorus ligands (1996)
    Springer
    Chromatographia 43 (1996), S. 491-495 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Rhenium bipyridine complexes ; Phosphorus ligand ; Inorganicity/organicity ratio ; Retention behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The high-performance liquid chromatography of fourteen rhenium complexes with phosphorus and 2,2′-bipyridine-derivative ligands has been examined. Good separation between these complexes was achieved by use of an ODS column with a 60∶40 (v/v) mixture of MeOH and KH2PO4-NaOH buffer as mobile phase. Linear correlations were observed between the capacity factors of the mono-phosphorus complexes and Fujita's organicity/inorganicity ratios for the phosphorus ligands, revealing that Fujita's organicity/inorganicity parameters are useful for evaluating of the retention behavior of these complexes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02292999
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    Urine clean-up method for determination of six arsenic species by LC-AAS involving microwave assisted oxidation and hydride generation (1996)
    Springer
    Chromatographia 43 (1996), S. 507-512 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Urine clean-up ; Arsenic speciation ; Microwave assisted oxidation ; Atomic absorption spectrometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An effective clean-up method based on the precipitation of most high molecular mass inorganic salts and organic compounds in ethanol at −15°C has been developed for the determination of arsenite, arsenate, monomethylarsonate (MMA), dimethylarsinate (DMA), arsenobetaine (AsB) and arsenocholine (AsC) in urine. Analyte recovery was close to 100%. The six species were separated on an anionic HPLC column and determined by microwave-assisted oxidation-hydride generation-atomic absorption spectrometry. The detection limits and relative standard deviation of the whole procedure were within the 8–15 μg L−1 and 2.5–5.3% ranges, respectively, which allows application to the analysis of urine of people exposed to arsenic.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02293002
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    Influence of organic modifier and temperature on the enantiomeric separation of γ-lactams by HPLC (1996)
    Springer
    Chromatographia 43 (1996), S. 365-368 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Enantioseparation ; Chiralcel OD ; γ-Lactams
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A high-performance liquid chromatographic method is reported for the resolution of the enantiomers of a series of fused γ-lactams (2,7-diaza-3-oxo[3.3.0]octan-6-ones) with probable anti-HIV and anticancer activity. Resolution was achieved on a Chiralcel® OD column, cellulose tris-(3,5-dimethylphenyl carbamate) adsorbed on macroporous silica gel; mixtures ofn-hexane and isopropyl alcohol in different proportions were used as the mobile phase. The analysis was studied at different temperatures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02271012
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    Simultaneous determination of tetrahydro-β-carbolines and β-carbolines (1996)
    Springer
    Chromatographia 43 (1996), S. 419-425 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Fluorimetric detection ; Tetrahydro-β-carbolines ; β-Carbolines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Reversed-phase ion-pair HPLC with fluorimetric detectors connected in series was studied for the simultaneous determination of two tetrahydro-β-carbolines and two β-carbolines. After additon of internal standards the samples were reacted with fluorescamine, and then subjected to serial extractions to remove their precursor (tryptamine) from the analytical system. This treatment not only suppressed the artefactual formation of tetrahydro-β-carbolines and β-carbolines during analysis, but also effectively purified them. Under optimum conditions, using trifluoroacetic acid as counter ion, all analytes were separated within 14 min and without major interfering peaks. The quantitative ranges were 0.25–80.0 ng mL−1 for both tetrahydro-β-carbolines and 0.1–30.0 ng mL−1 for both β-carbolines. Replicate spiking experiments showed that recovery from most of the samples tested was over 90% and the relative standard deviation ranged from 0.7 to 10.4% within and between assays. The proposed method was applicable to various materials such as soy sauce, vinegar, ketchup, tabasco, beer, wine, sake, whisky, brandy, cows' milk, coffee, cocoa, cheese, cigarette smoke and urine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02271022
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    Short-term measurements of acrolein in ambient air (1996)
    Springer
    Chromatographia 43 (1996), S. 433-435 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Atmospheric acrolein ; DNPH derivatization ; High-volume scrubber
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method has been developed for the determination of acrolein in air samples collected by a high-volume aqueous scrubber. The aldehyde is collected as the bisulfite adduct, which is decomposed before determination of acrolein by DNPH (2,4-dinitrophenylhydrazine) derivatization and HPLC. Approximately 95% of the acrolein reacts with DNPH within 3 h at DNPH:HSO3 molar ratios of up to 10. The method appears promising for short-term air sampling at 8 L min−1, enabling the achievement of a detection limit of 0.2 μg m−3 for acrolein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02271025
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    Polyethylene-coated silica and zirconia stationary phases in view of quantitative structure-retention relationships (1996)
    Springer
    Chromatographia 43 (1996), S. 484-490 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Polyethylene-coated silica ; Polyethylene-coated zirconia ; Linear free energy relationships (LFER) ; Quantitative structure-retention relationships (QSRR)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Retention properties of two new high-performance liquid chromatographic (HPLC) stationary phases, polyethylene-coated silica (PECSiO2) and polyethylene-coated zirconia (PECZrO2), were compared chemometrically. Reversed phase HPLC capacity factors were determined isocratically for a carefully designed series of 25 structurally diverse solutes. Linear free energy relationship (LFER)-based solute parameters (excess molar refraction, dipolarity-polarizability, hydrogen-bond acidity and basicity, McGowan volume) and solute structural descriptors determined by physico-chemical methods (water accessible van der Waals volume, dipole moment, atomic electron excess charge) were regressed as independent variables against log capacity factors. The quantitative structure-retention relationships (QSRR) obtained show the predominating partition mechanism of separation on both phases. Both the LFER parameters and the structural parameters obtained by molecular modelling produced QSRR equations of high and practically identical retention prediction ability. It has been concluded that intermolecular interactions of the dipolarity-polarizability type manifest themselves more strongly on the silica-based phase than on the zirconia-based one. This can be due to a role of active free silanols on the silica support.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02292998
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 76
    Electronic Resource
    Electronic Resource
    Open tubular liquid chromatography using a sol-gel derived stationary phase (1996)
    Springer
    Chromatographia 43 (1996), S. 477-483 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Open tubular columns ; Sol-gel coatings ; Laser-induced fluorescence detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An organically modified silica glass material containing octyl groups (C8) was fabricated by the sol-gel process and coated onto the inner walls of fused silica capillaries. The coating was used as the stationary phase for reversed-phase open tubular liquid chromatography (OTLC). The sol-gel process facilitated the fabrication of a porous silica glass layer with the stationary phase in one single step. The high surface area of the coating, characteristic of materials fabricated by the sol-gel process, resulted in capillary columns with a stronger retention than those prepared by a conventional procedure. The molar ratio of the precursors was used as a tunable parameter to adjust the retention and selectivity of the stationary phase. The column performance was evaluated using anthracene derivatives as model analytes which were monitored by laser-induced fluorescence (LIF) detection. Separation efficiencies of 200,000 theoretical plates/meter were typical for the model compounds. Solute selectivity of the sol-gel derived stationary phase was found to be similar to the selectivity of HPLC monomeric-type phases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02292997
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    Preparation of enzyme electrodes for clinical and toxicological analysis with application of the fast immobilization of enzymes and proteins on the affinity chromatography supports (1996)
    Springer
    Chromatographia 43 (1996), S. 513-521 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Affinity chromatography ; Fast immobilization of enzymes ; Clinical and toxicological analysis ; Urease (Urea amidohydrolase E.C. 3.5.1.5
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Immobilized enzymes or other biological active substances play an important role in the modern biochemistry, biotechnology, molecular biology, pharmacology and toxicology. One of the immobilizing methods is covalent bonding with insoluble supports. In the present experiment the aim was to use affinity chromatography gels for fast immobilization of enzymes and proteins; hexamer and monomer of urease (E.C. 3.5.1.5 Urea Amidohydrolase) were used. The enzyme was immobilized on several different supports for affinity chromatography (covalent chromatography, bioaffinity chromatography and chromatography on immobilized mercurials). Differences in yields of immobilization and catalytic activity of heterogenized enzymes were found. The best properties for the immobilization of polyisoenzymes were gels for covalent affinity chromatography and bioaffinity chromatography using hydroxyurea as ligand. The optimal length of the spacer arm used for immobilization was about 10–15 atoms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02293003
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 78
    Electronic Resource
    Electronic Resource
    Preparation and separation of metallobacteriochlorophylla by reversed-phase high-performance liquid chromatography (1996)
    Springer
    Chromatographia 43 (1996), S. 361-364 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Bacteriochlorophylla ; Copper(II) bacteriochlorophylla ; Zinc(II) bacteriochlorophylla
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Semi-preparative high-performance liquid chromatography has been used for the preparation of copper(II) bacteriochlorophylla [Cu(II)-BChl-a] and zinc(II) bacteriochlorophylla [Zn(II)-BChl-a]. Both compounds are separated on a reversed-phase Inertsil ODS-2 column using a mobile phase of acetone-methanol (25∶75, v/v). The fractionated metallobacteriochlorophylls (M-Bchl-a) are identified by fast atom bombardment mass spectrometry. The spectroscopic parameters such as the wavelength of absorption maxima and the molar extinction coefficients are determined using pure M-Bchl-a obtained by preparative HPLC. The HPLC method proposed here has been demonstrated to be useful for the purification and determination of components of M-Bchl-a.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02271011
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 79
    Electronic Resource
    Electronic Resource
    Assay of four stereoisomers of desacetyl diltiazem hydrochloride. Application toin vitro chiral inversion studies (1996)
    Springer
    Chromatographia 43 (1996), S. 413-418 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Desacetyl diltiazem hydrochloride stereoisomers ; Chiralcel OF ; Chiral inversion ; Epimerization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Direct resolution of four stereoisomers of the related compound of diltiazem hydrochloride, namely desacetyl diltiazem hydrochloride, was studied by both normal and reversed-phase chiral HPLC. The four stereoisomers were completely resolved on a Chiralcel OF column. The technique developed was applied to a chiral inversion study of desacetyl diltiazem hydrochloride. This inversion was observed neither in the solid state, in aqueous solution at 100°C for 3 h nor under visible light for 10h, but was observed in aqueous solution under UV irradiation. The (+)-(2S, 3S)-cis-desacetyl diltiazem hydrochloride degraded with a half-life of 1.9 h in aqueous solution under UV and epimerized to (+)-(2R, 3S)-trans-desacetyl diltiazem hydrochloride. Similarly, (+)-(2S, 3S)-cis-desacetyl diltiazem hydrochloride degraded about three times faster than diltiazem hydrochloride. Reverse epimerization of (+)-(2R, 3S)-trans-desacetyl diltiazem hydrochloride to (+)-(2S, 3S)-cis-desacetyl diltiazem hydrochloride was not observed. The overall degradation was the result of two competitive processes, the epimerization and the decomposition of the benzothiazepin ring. The degradation and epimerization rate of (+)-(2S, 3S)-cis-desacetyl diltiazem hydrochloride in solution under UV depended upon the solvent, the aqueous pH, and concentration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02271021
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    Determination of free aliphatic aldehydes in plasma by high-performance liquid chromatography of the 1,3-cyclohexanedione derivatives (1996)
    Springer
    Chromatographia 43 (1996), S. 501-506 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Aldehydes, aliphatic ; 1,3-Cyclohexanedione (CHD) ; Fluorimetric detection ; Plasma analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple and sensitive method is proposed for the measurement of aldehydes in plasma. The plasma samples are treated with 1,3-cyclohexanedione (CHD) and after addition of the internal standard (the CHD derivative of octaldehyde) are analysed by reversed-phase high-performance liquid chromatography with an acetonitrile-water gradient as the mobile phase. Detection is by fluorimetry with excitation at 395 nm and emission at 457 nm. In plasma samples spiked with aldehydes, the calibration curves showed good linearity in the range 0–10 μg mL−1. The recoveries of aldehydes were quantitative; coefficients of within-day and between-day variation were less than 13% and 11%, respectively. Applications to human and some animal plasma samples are reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02293001
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...