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  • 1
    Electronic Resource
    Electronic Resource
    Monolithic Silica Columns for HPLC, Micro-HPLC, and CEC (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 111-116 
    Details
    ISSN: 0935-6304
    Keywords: Monolithic column ; silica monolith ; HPLC ; capillary liquid chromatography ; capillary electrochromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Two types of monolithic silica columns derivatized to form an ODS phase, one prepared in a fused silica capillary (SR-FS) and the other prepared in a mold and clad with an engineering plastic (poly-ether-ether-ketone) (SR-PEEK), were evaluated. The column efficiency and pressure drop were compared with those of a column packed with 5-μm ODS-silica particles and of an ODS-silica monolith prepared in a mold and wrapped with PTFE tubing (SR-PTFE). SR-FS gave a lower pressure drop than a column packed with 5-μm particles by a factor of 20, and a plate height of 20 μm at a linear velocity below 1 mm/s. SR-PEEK showed higher flow-resistance than the other monolithic silica columns, but they still showed a minimum plate height of 8-10 μm and a lower pressure drop than popular commercial columns packed with 5-μm particles. The evaluation of SR-FS columns in a CEC mode showed much higher efficiency than in a pressure-driven mode.
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  • 2
    Electronic Resource
    Electronic Resource
    Optimization and Validation of a Fast Liquid Gradient for Determination of Prominent Flavan-3-ols and Flavonols in Fresh Vegetables (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 637-643 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; fast separation ; flavan-3-ol ; flavonols ; vegetables ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A fast high-performance liquid chromatography method was used for analysis of prominent flavan-3-ols and flavonols in vegetables. Gradient elution with phosphoric acid-acetonitrile mixtures and phosphoric acid-methanol mixtures allowed fast and complete separation of the studied phenolic compounds within analysis times less than 10 min. The development of two elution gradients using methanol and acetonitrile as modifiers proved to be an excellent approach for the verification of the real polyphenolic composition in vegetables samples because the two optimized methods allowed the separation of the same number of compounds in the same elution order. Diode-array detection was employed for the provisional identification of phenolic compounds that were not available as standards. We preferred methanol as a modifier because it was less toxic and cheaper than acetonitrile. Detection limits ranged between 0.12 and 0.59 μg mL-1. High recoveries of phenolics from fresh vegetables were measured in all studied cases, independent of the phenolic structure, matrix, and vegetable in question. High levels of procyanidins between 150 and 450 mg kg-1 were found in all studied vegetables. Quantification of quercetin and kaempferol glycosides was only possible in marrow and onion, respectively.
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  • 3
    Electronic Resource
    Electronic Resource
    Reversed-Phase High-Performance Liquid Chromatographic Separation and Determination of 4-Amino-azobenzene-4′,5-disulfonic Acid and Related Products in Industrial Wastewater Effluents (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 329-332 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; industrial wastewater ; process development ; 4-amino-azobenzene-4′,5-disulfonic acid (AABDS) ; 4-amino-azobenzene (AAB) ; 4-amino-azobenzene-4′-sulfonic acid (AABS) ; 4-amino-azobenzene-4′,3,5-trisulfonic acid (AABTS) ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A simple and rapid reversed-phase high-performance liquid chromatographic method for the separation and determination of 4-amino-azobenzene-4′,5-disulfonic acid (AABDS) and its process-related impurities was developed. The separation was achieved on a μ-Bondapak C18 column using 0.15 M ammonium sulfate-acetonitrile (55:45) (v/v) as eluent. A UV-visible spectrophotometric detector fixed at 386 nm was used both for detection and quantitation. The method was used not only for quality assurance but also for process development and wastewater management of AABDS.
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  • 4
    Electronic Resource
    Electronic Resource
    A New Monolithic-Type HPLC Column For Fast Separations (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 93-99 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; monolithic column ; silica rod column ; fast separations ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The application of a new silica-based, monolithic-type HPLC-column for fast separations is presented. The column is prepared according to a new sol-gel process, which is based on the hydrolysis and polycondensation of alkoxysilanes in the presence of water soluble polymers. The method leads to “rods” made of a single piece of porous silica with a defined pore structure, i. e. macro- and mesopores. The main feature of silica rod columns is a higher total porosity, about 15% higher than of conventional particulate HPLC columns. The resulting column pressure drop is therefore much lower, allowing operation at higher flow rates including flow gradients. Consequently, HPLC analysis can be performed much faster, as it is demonstrated by various applications.
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  • 5
    Electronic Resource
    Electronic Resource
    High Resolution Separation of Non-Polar Lipid Classes by HPLC-ELSD Using Alumina as Stationary Phase (1999)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 22 (1999), S. 483-486 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; alumina ; evaporative light-scattering detection ; non-polar lipids ; wax esters ; sterol esters ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---This study describes the performance and capacity of alumina as stationary phase in an HPLC-ELSD (evaporative light-scattering detection) method optimized for the separation of the non-polar lipid classes hydrocarbons, wax esters, sterol esters, triacylglycerols, and sterols, including quantitative determination of these lipid classes in natural samples. By using gradient elution and constant equilibration times between injections, highly reproducible separations of triacontane, stearyl oleate, and cholesterol oleate were accomplished with a binary mobile phase system. Phase A contained 0.5% tetrahydrofuran in hexane and phase B 20% isopropanol and 20% tetrahydrofuran in hexane. The same system was also used to determine the non-polar lipid classes in a zooplankton sample, the major lipid class being wax esters, followed by triacylglycerols, sterol esters, sterols, and hydrocarbons. Substantial amounts of an unknown compound, possibly acylated glyceryl ethers, were also found. The equilibration time of alumina was relatively slow compared to a polyvinyl alcohol stationary phase used earlier by the authors and calibration curves for different lipid classes were more uniform and linear with alumina.
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  • 6
    Electronic Resource
    Electronic Resource
    Determination of Biological Oxidative Stress Using High Performance Liquid Chromatography with Electrochemical Detection (HPLC-ECD) (1999)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 22 (1999), S. 429-437 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; nitrotyrosine ; nitrotocopherol ; analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---For three decades, high performance liquid chromatography has proven itself to be a powerful, flexible, and inexpensive tool for basic and clinical research. Recent advances in our understanding of disease have prompted a demand for more sensitive and selective methods of routine bioanalysis, particularly with respect to the determination of oxidative metabolites and biomarkers of oxidative stress. Multidimensional detectors utilizing coulometric arrays offer a solution to these research needs. The challenge to the bioanalyst is now to creatively apply HPLC-ECD technology to promising research and clinical enterprises.
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  • 7
    Electronic Resource
    Electronic Resource
    New Stationary Phase Prepared by Immobilization of a Copper-Amine Complex on Silica and Its Use for High Performance Liquid Chromatography (1999)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 22 (1999), S. 103-108 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; stationary phase ; copper-amine complex ; aromatic amines ; polyaromatic hydrocarbons ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Chromatographic silica (10 μm) was chemically modified with the silylating agent: [3-(2-aminoethyl)aminopropyl]trimethoxysilane (AEAPTS). The reaction product was characterized by elemental analysis and infrared and 13C and 29Si NMR spectra. The chemically modified silica was treated with Cu(II) in methanol medium. This cation was strongly adsorbed through complexation by the pendant ethylenediamine groups attached to the silica surface. The complex formed on the silica surface was shown to be stable in both aqueous and non-aqueous media. The aim of Cu(II) immobilization is to use this new material as a stationary phase in High Performance Liquid Chromatography (HPLC). Separations of synthetic mixtures of aromatic amines and of polyaromatic hydrocarbons were undertaken using 150×3.9 mm HPLC columns packed with the modified silica, with and without copper ions, to follow the influence of the cation on the chromatographic separation and to verify the efficiency of the new stationary phase for HPLC.
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  • 8
    Electronic Resource
    Electronic Resource
    Study of the Linear Range in HPLC Analyses with UV Detection: Methodology and Experimental Application to the Influence of the Analyte UV Spectrum (1999)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 22 (1999), S. 217-221 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; UV detection ; linear range ; method validation ; Beer-Lambert law ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Determination of the linear range is one of the main concerns in validation of an HPLC analysis method. It is particularly important since single point calibration will be then used routinely. We proposed an iterative methodology to handle this problem. The idea was, at each step, to test statistically whether the following point belonged to the same regression line. The methodology was then used to evaluate quantitatively the effect on linear range of a shift in detection wavelength or of the detector bandwidth. Although experimental results were globally in accordance with spectroscopic theory, magnitudes observed were rather large. So the linear range could vary by a factor of over 2 with changes in conditions that remained within the range of current practical values. Changes in detection wavelength were limited to about fifteen nm around λmax and the detector used was considered to be representative of modern high-performance UV detectors. The question of how to take consequences in method validation into account was raised. The solution proposed recommended that the validation was undertaken in conditions as close as possible to those where the method would be conducted routinely. This means with the same instrumentation and on the product of interest for analyses.
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  • 9
    Electronic Resource
    Electronic Resource
    High Performance Liquid Chromatographic Screening and Gas Chromatography-Mass Spectrometry Confirmation of Tebuthiuron Residues in Drinking Water (1999)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 22 (1999), S. 239-241 
    Details
    ISSN: 0935-6304
    Keywords: Tebuthiuron ; GC-MS ; HPLC ; drinking water ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
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  • 10
    Electronic Resource
    Electronic Resource
    Determination of the Specific Migration of DEHP into Food Simulants Using High Performance Liquid Chromatography (1999)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 22 (1999), S. 70-72 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; di(2-ethylhexyl) phthalate ; migration ; foods and food simulants ; PVC cling film ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 11
    Electronic Resource
    Electronic Resource
    Chiral recognition of phthalides and lactams (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 10 (1998), S. 430-433 
    Details
    ISSN: 0899-0042
    Keywords: Whelk-O 1 ; chromatography ; HPLC ; enantiodifferentiation ; heterocycles ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In concert with a larger study of the processes by which chiral stationary phase CSP 1 differentiates between enantiomers, we have investigated the chromatographic separation of the enantiomers of a series of aryl-substituted heterocycles of systematically varied structure. A mechanistic picture of how these and similar resolutions occur is emerging. The mechanistic hypothesis described herein is of predictive value. Chirality 10:430-433, 1998. © 1998 Wiley-Liss, Inc.
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  • 12
    Electronic Resource
    Electronic Resource
    Achiral derivatization as a means of improving the chromatographic resolution of racemic alcohols on benzoylcellulose CSPs (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 10 (1998), S. 492-498 
    Details
    ISSN: 0899-0042
    Keywords: racemate ; enantiomer ; HPLC ; chiral stationary phase ; benzoylcellulose ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The advantages that can be gained from derivatization of various racemic aliphatic and aromatic alcohols prior to enantiomeric chromatographic separation have been systematically investigated for a series of benzoate derivatives. Three cellulose-based CSPs available in the pure polymeric form - tribenzoyl cellulose (TBC), meta-methylbenzoyl cellulose (MMBC), and para-methylbenzoyl cellulose (PMBC) - were selected and several benzoate derivatives varying in the nature and the position of the substituent on the benzoyl group were prepared and analysed. TBC clearly gives the broadest application range, and among the different benzoate esters the best selectivity was generally obtained with either the 4-methoxybenzoate or the 4-methylbenzoate derivatives. Based on these results, some empirical rules could be formulated for optimizing the enantiomeric separation of racemic alcohols, which make up one of the most important classes of chemical substances used as drugs and biocides, or as building blocks for their synthesis. An application of this approach to the preparative separation of the enantiomers of a drug intermediate is also shown. Chirality 10:492-498, 1998. © 1998 Wiley-Liss, Inc.
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  • 13
    Electronic Resource
    Electronic Resource
    Enantioselective determination of isradipine in human serum using chiral stationary phase liquid chromatography and gas chromatography with nitrogen selective detection (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 10 (1998), S. 808-812 
    Details
    ISSN: 0899-0042
    Keywords: calcium antagonist ; stereoselective analytical method ; isradipine enantiomers ; Chiral OJ ; HPLC ; GC ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: rac-Isradipine is a dihydropyridine type calcium antagonist. Its calcium entry blocking effect is due primarily to the (+)-(S)-enantiomer. This study describes a sensitive enantioselective method for the determination of isradipine in human serum. Following alkaline extraction into hexane, the enantiomers of isradipine are separated quantitatively by high-performance liquid chromatography on a Chiralcel OJ column at 39°C. The collected fractions were evaporated and assayed using capillary gas chromatography on a HP 50+ column with nitrogen selective detection. Using 2.0 ml of serum, 0.7 nmol/1 (0.26 ng/ml) of each enantiomer could be determined with acceptable precision. The method has successfully been used to measure (+)-(S)- and (-)-(R)-isradipine concentrations in samples from volunteers after intravenous and oral administration of isradipine. Chirality 10:808-812, 1998. © 1998 Wiley-Liss, Inc.
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  • 14
    Electronic Resource
    Electronic Resource
    Synthesis of (1→6)-2,5-anhydro-D-glucitol through cyclopolymerization of 3,4-di-O-allyl-1,2 : 5,6-dianhydro-D-mannitol and optical resolution ability of its derivative in HPLC (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 901-909 
    Details
    ISSN: 0887-624X
    Keywords: (1→6)-2,5-anhydro-D-glucitol ; HPLC ; optical resolution ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cyclopolymerization of 3,4-di-O-allyl-1,2 : 5,6-dianhydro-D-mannitol (1) was carried out using BF3·OEt2 and t-BuOK. The polymer obtained by the polymerization with BF3·OEt2 mainly consisted of (1→6)-bonded 3,4-di-O-allyl-2,5-anhydro-D-glucitol as the five-membered constitutional repeating unit, though it contained a small amount of other cyclic repeating units. On the other hand, during the polymerization using t-BuOK, the stereoregular polymer (1→6)-linked 3,4-di-O-allyl-2,5-anhydro-D-glucitol (2) was synthesized via a regio- and stereoselective mechanism. Cleavage of the allyl ether linkage in polymer 2 occurred to produce the polymer consisting of only 2,5-anhydro-D-glucitol units, i.e., (1→6)-2,5-anhydro-D-glucitol (3). Chromatographic enantioseparation of chloroquine and tröger base has been performed on (3,5-dimethylphenyl)carbamate and 4-methylbenzoate derivatives of 3 as a chiral stationary phase for high-performance liquid chromatography. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 901-909, 1998
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  • 15
    Electronic Resource
    Electronic Resource
    Chiral Resolution of RR, SS-Hydrobenzoin by Liquid Chromatography Using Borate-Cyclodextrin Complexation (1998)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 21 (1998), S. 414-416 
    Details
    ISSN: 0935-6304
    Keywords: chiral separation ; HPLC ; diols ; borate complexation ; cyclodextrin ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 16
    Electronic Resource
    Electronic Resource
    Off-Line LC-LC Determination of PAHs in Edible Oils and Lipidic Extracts (1998)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 21 (1998), S. 253-257 
    Details
    ISSN: 0935-6304
    Keywords: Edible oils ; lipids in foods ; HPLC ; Polycyclic Aromatic Hydrocarbons (PAHs) ; off line LC-LC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 17
    Electronic Resource
    Electronic Resource
    Determination by HPLC of adrenalin (E) and of noradrenalin (NE) in certain species of mesopelagic fish in the Strait of MessinaThis paper has not bee peer reviewed (1998)
    New York : Wiley-Blackwell
    Journal of Bioluminescence and Chemiluminescence 13 (1998), S. 311-314 
    Details
    ISSN: 0884-3996
    Keywords: bioluminescence ; adrenalin ; noradrenalin ; photophores ; HPLC ; mesopelagic fish ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The presence of adrenalin (E) and noradrenalin (NE) was found by HPLC both in the photophores and at other tissue levels of numerous species of mesopelagic fish in The Strait of Messina, with the aim of determining the incidence of these catecholamines in photophores, in light transmission and the eventual presence at other tissue levels. © 1998 John Wiley & Sons, Ltd.
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  • 18
    Electronic Resource
    Electronic Resource
    Dolichol-like lipids with stimulatory effect on DNA synthesis: Substrates for protein dolichylation? (1998)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 71 (1998), S. 502-514 
    Details
    ISSN: 0730-2312
    Keywords: HMG-CoA ; MVA ; HPLC ; dolichol-like lipids ; DNA synthesis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Substantial evidence has suggested that a nonsterol product of mevalonic acid (MVA) is essential for the initiation of DNA synthesis in mammalian cells. Several possible isoprenoid candidates have been suggested, but the identity of this compound still remains unknown. In this study we have isolated and purified MVA products from SV40-transformed human fibroblasts and identified fractions with a growth-stimulatory effect. The cells were labelled with [14C]MVA in the presence of inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase. After lipid extraction, the [14C]MVA-labelled lipids were subjected to high performance liquid chromatography and size-exclusion chromatography, and the effect of the fractionated eluate on the DNA synthesis of arrested MVA-depleted target cells was tested. Thereby we found a fraction of [14C]MVA-labelled lipids with a substantial stimulatory effect on DNA synthesis. The chromatographic behavior suggested that the growth-stimulating fractions contained dolichol-20. This was confirmed by mass spectrometric analysis. Similar results were obtained when lipids from hepatocellular carcinoma cells and a sample from breast tumor were isolated and analyzed by the same procedure. The mechanisms by which these compounds induce DNA synthesis are unknown. Recent data obtained in our laboratory have provided evidence that dolichyl groups are covalently linked to tumor cell proteins, which implicates a new biological function for long-chain polyisoprenoid alcohols (Hjertman et al. [1997] FEBS Lett 416:235-238). In this study we demonstrate that tumor cells containing dolichol-like growth-stimulatory lipids also contained dolichylated proteins. This raises the question whether the growth-stimulatory dolichol-like lipids serve as substrates for the dolichylation reaction. J. Cell. Biochem. 71:502-514, 1998. © 1998 Wiley-Liss, Inc.
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  • 19
    Electronic Resource
    Electronic Resource
    Enantioseparation on 4-halogen-substituted phenylcarbamates of amylose as chiral stationary phases for high-performance liquid chromatography (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 9 (1997), S. 63-68 
    Details
    ISSN: 0899-0042
    Keywords: enantioseparation ; chiral stationary phase ; HPLC ; amylose phenylcarbamate ; chiral discrimination ; resolution ; enantiomer ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Four 4-halogen-substituted phenylcarbamate derivatives of amylose were prepared and their chiral recognition abilities as chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC) were evaluated and compared with those of the corresponding cellulose derivatives. The amylose derivatives with fluoro, chloro, bromo, or iodo group at the four-position on the phenyl group were found to show higher chiral resolving ability than the corresponding cellulose derivatives. Among four amylose derivatives 4-fluoro- and 4-chlorophenylcarbamates showed an excellent chiral recognition ability. Especially, amylose tris(4-chlorophenylcarbamate) resolved (±)-1,2,2,2-tetraphenylethanol with a very high α value (α = 8.29). In order to obtain useful information concerning the chiral recognition mechanism of this resolution, we also performed enantioseparation of a variety of analogous racemic alcohols, and found that both the hydroxy and bulky triphenylmethyl groups of the racemate are essential for the effective chiral recognition. Chirality 9:63-68, 1997. © 1997 Wiley-Liss, Inc.
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  • 20
    Electronic Resource
    Electronic Resource
    Optical rotation detection for reversed phase HPLC: Investigation of solvent effects (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 9 (1997), S. 122-125 
    Details
    ISSN: 0899-0042
    Keywords: enantiomeric excess determination ; polarimetry ; HPLC ; enantiomers ; solvent effects ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Investigations into the parameters affecting the sensitivity of polarimetric detectors for the determination of enantiomeric excess by achiral HPLC are presented. The results obtained showed that the specific optical rotation of an analyte was highly sensitive to the methanol content of the mobile phase. The purpose of this short communication is to demonstrate that “off-line” optical rotation measurements are a necessary part of the method development process for successful use of polarimetric detectors. Chirality 9:122-125, 1997, © 1997 Wiley-Liss, Inc.
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  • 21
    Electronic Resource
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    Enantioselective determination of FCE 28833, a new potential antiischemic agent, in gerbil plasma using column switching HPLC with UV detection (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 9 (1997), S. 133-138 
    Details
    ISSN: 0899-0042
    Keywords: anti-ischemic agent ; gerbil ; enantiomeric resolution ; column switching ; chiral crown ether ; HPLC ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A sensitive and selective high performance liquid chromatographic method using an automated column switching technique for the determination of FCE 28833 enantiomers in gerbil plasma was developed. After solid-liquid extraction using a Supelcosil C18 cartridge FCE 28833 was eluted on a clean-up column (Spherisorb CN) and the enantiomers were separated using an analytical chiral column (Crownpack CR(+)). The mobile phase (15% methanol in HClO4 1 mM) was directed through the columns at a flow rate of 1 ml/min and the fraction eluted between 13 and 40 min was transferred from the clean-up column into the analytical column. FCE 28833 enantiomers were monitored at 257 nm. The limit of quantitation of the method was 20 ng/ml plasma for both enantiomers and proved to be linear, precise, and accurate for the assay of both enantiomers in the 20-6,000 ng/ml concentration range. No interference from the blank gerbil plasma sample was observed. The suitability of the method was assessed using plasma samples obtained from male gerbils treated with a single oral dose (400 mg/kg) of FCE 28833. Chirality 9:133-138, 1997. © 1997 Wiley-Liss, Inc.
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  • 22
    Electronic Resource
    Electronic Resource
    Determination of the deprotonation constants of seleno-DL-cystine and seleno-DL-methionine and implication to their separation by HPLC (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 11 (1997), S. 21-30 
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    ISSN: 0268-2605
    Keywords: seleno-DL-cystine ; seleno-DL-methionine ; pKa ; HPLC ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We have determined the deprotonation constants (pKa) of seleno-DL-cystine and seleno-DL-methionine together with those of DL-cystine and DL-methionine for comparison, by potentiometric measurements. In the case of seleno-DL-cystine, the difference between the pKa values for the two amino groups was found to be only slightly lower than that observed for DL-cystine itself. In contrast, the difference between the two pKa values for the carboxylic groups was found to be much smaller for seleno-DL-cystine than for DL-cystine. In both seleno-amino-acids, the zwitterionic species appear to be dominant in the pH range between 4 and 7, while positively charged protonated species are found to be present at pH values lower than 4. Based on a knowledge of the ionic species distributions as a function of pH, we have proposed an interpretation for the chromatographic separation of selenocystine and selenomethionine by HPLC. © 1997 by John Wiley & Sons, Ltd.
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    Chromatography of functional polymers: A new approach to the characterization of reactive polymers obtained by chemical modification (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 1173-1180 
    Details
    ISSN: 0887-624X
    Keywords: chemical composition distribution ; liquid chromatography ; porous polymer beads ; HPLC ; monodisperse particles ; poly(isobutylene-co-4-methylstyrene) ; bromination ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High-performance liquid chromatography (HPLC) has been used to complement size-exclusion (gel permeation) chromatography (SEC) for the characterization of functional polymers. Whereas SEC is unable to detect compositional changes, HPLC in an appropriate interacting medium can provide detailed information on compositional changes occurring during chemical modification of a polymer. The method has been demonstrated using a normal-phase column consisting of porous monodisperse 10 μm poly(2,3-dihydroxypropyl methacrylate-co-ethylene dimethacrylate) beads that have a homogeneous coverage of aliphatic hydroxyl groups for the analysis of brominated poly(isobutylene-co-4-methylstyrene). Differences of well below 1 mol % of bromomethylstyrene units are easily detected and quantified. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1173-1180, 1997
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    Preparation and functionalization of reactive monodisperse macroporous poly(chloromethylstyrene-co-styrene-co-divinylbenzene) beads by a staged templated suspension polymerization (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 2631-2643 
    Details
    ISSN: 0887-624X
    Keywords: macroporous beads ; poly(chloromethylstyrene) ; chiral separation ; HPLC ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactive monodisperse porous poly(chloromethylstyrene-co-styrene-co-divinylbenzene) beads have been prepared by a staged templated suspension polymerization method with different concentrations of linear polystyrene porogen and chloromethylstyrene in the polymerization mixture. The presence of a small amount of linear polystyrene in the polymerization mixture leads to a dramatic increase in both the pore size and the pore volume of the resulting beads. In contrast, addition of chloromethylstyrene leads to lower surface areas and smoother surfaces due to the reduced compatibility between the polystyrene porogen and the newly formed crosslinked chains. The modification of chloromethylstyrene beads by Gabriel synthesis to obtain aminated beads has also been studied. The final number of primary amino groups is related to the starting concentration of functional benzyl chloride moieties rather than to the porous properties. Both π-basic and π-acidic type chiral selectors, (R)-1-(1-naphthyl)-ethylamine and (R)-N-(3,5-dinitrobenzoyl)phenylglycine, respectively, have been attached to the amino functionalized beads, and the resulting chiral beads have been used in the model HPLC separations of enantiomers. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2631-2643 1997
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    Isolation and determination of toxic congeners of polychlorinated biphenyls in environmental samples (1997)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 20 (1997), S. 1-9 
    Details
    ISSN: 0935-6304
    Keywords: GC-MS ; HPLC ; Non-ortho ; mono-ortho ; di-ortho substituted polychlorinated biphenyls (PCBs) ; 2-(1-Pyrenyl)ethyldimethylsilylated silica column ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A Method has been developed for the separation and enrichemen of there non-ortho, eight mono-ortho, and di-ortho substituted polychlorinated biphenyls (PCBs) from Aroclor formulations and environmental samples. The fractionation is accomplished using high performance liquid chromatography (HPLC) with a 2-(1-pyrenyl)ethyldimethylsilysily silca column. GC-MSD with an optimized temperature program was used for quantitation, Hexane, pentane, cyclohexane, iso-octane, and 2-propanol were tested as a mobile phase for the isolation of the thirteen target PCBs in a Aroclor 1242, 1254, and 1260 (1:1:1) misture, Pentane at room temperature with a slow rate of 0.7 ml/min is the condition of choice. The average recovery of thirteen target PCBs spiked in the Aroclor mixture is 99.5% with an average relative standard deviation of 4.5%. The average method detection limit is 8pg/μl. Targer PCBs in the reference solis, incinarator ash, and sediment samples were measured.
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    Simultaneous determination of nicotinamide, nicotinic acid, riboflavin, thiamin, and pyridoxine in enriched Brazilian foods by HPLC (1997)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 20 (1997), S. 245-248 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; Enriched foods ; Simultaneous determination ; Vitamin analyses ; B-group vitamins ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The control of the enrichment levels in foods is difficult, due mainly to the lack of appropriate analytical methodologies. The amounts of the five B-group vitamins (nicotinamide, nicotinic acid, ribofla-vin, thiamin, and pyridoxine) have been determined in enriched Brazilian foods by a high-performance liquid chromatography (HPLC) method. Fifty products, such as biscuits, liquid and dry milks, flavored milk drinks, flour, macaroni, and cereals were analyzed. Some products showed the amounts declared on the package. Although some slight quantitative variations were shown in the biscuits, one showed levels of riboflavin 35% lower than the value declared. Of five different corn cereal brands, only one showed the declared vitamin content, the others showing levels 30 % lower than that declared. No B-group vitamins were detected in one brand of enriched macaroni, except for the nicotinic acid naturally present in the flour. On the other hand, one flavored milk drink exhibited vitamins levels 200% higher than the amounts declared and one milk drink mix presented thiamin, riboflavin, and nicotinamide levels 3 to 5 times greater than stated. These results suggest an absence of control of the amount of vitamins in enriched foods.
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    A reversed phase high-performance liquid chromatography method for determination of cephalexin in human plasma (1997)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 20 (1997), S. 674-678 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; LC-MS/MS ; Validation ; Cephalexin ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A reversed-phase HPLC method for the analysis of cephalexin (7-[(aminophenylacetyl)amino]-3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid) by isocratic separation is described. A comparison is made between the ultrafiltration land the extraction procedure developed in our laboratory. The extraction procedure, based on the deproteinization of plasma with perchloric acid followed by the extraction with dichloroethane and separation of cephalexin on a reversed phase column, gave better recovery. Quantitative validation of our method has been performed by an external standard technique. The relative standard deviations were between 1.1 and 1.9% in the within-day assay and between 1.2 and 2.2% in the inter-day assay. The limit of detection was 0.14ug/ml and the limit of quantification was 0.28ug/ml. This method is rapid, sensitive, simple, and reproducible. The LC MS/MS technique was successfully used for identification and quantification of cephalexin in human plasma samples.
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    Analysis of non-polar lipids by HPLC on a diol column (1997)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 20 (1997), S. 516-518 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; Diol column ; Evaporative Light Scattering Detector ; Wax esters ; Triglycerides ; Fatty alcohols ; Fatty acids ; Monoglycerides ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    HPLC of nucleic acid components with volatile mobile phases part. 2: Separations on polymeric supports (1997)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 20 (1997), S. 693-696 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; Nucleotides ; 5′-Nucleotides ; 2′,3′-Nucleotides ; Myocardial compounds ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Stationary phases 44Part 43 of this series, see reference [1].: Chromatographic separation of naturally occurring dehydroiso-α-lapachone derivatives with C60-fullerencel stationary phase (1997)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 20 (1997), S. 624-628 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; C60-fullerene stationary phase ; Dehydroiso-α-lapachome ; Quinones ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Determination of acyclovir in plasma by high performance liquid chromatography with UV detection. Method development and method validation (1997)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 20 (1997), S. 503-506 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; Bioavailability ; Validation ; Acyclovir ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A HJPLC method for the determination of acyclovir in plasma is described. The method is simple and sensitive enough for bioequiva-lence studies, where a large number of plasma samples with low acyclovir concertration are involved. The procedure is based on the deproteinization of plasma with perchloric acid and separation of acyclovir on a Hypersil ODS Column at pH 5.6 with UV detection. The calibration standards are linear up to at least 4000 ng/mL and the limit of quantification is 10 ng/mL.
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    Opioid peptides derived from hemoglobin: Hemorphins (1997)
    New York : Wiley-Blackwell
    Biopolymers 43 (1997), S. 75-98 
    Details
    ISSN: 0006-3525
    Keywords: hemoglobin ; opioid peptides ; HPLC ; macrophages ; pepsin ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Investigation of hemoglobin peptic hydrolysate has revealed the presence of biologically active peptides with affinity for opioid receptors. Two peptides, VV-hemorphin-7 and LVV-hemorphin-7, were resolved by a combination of size exclusion and reversed phase HPLC. A new spectroscopic method based on the second order derivative spectra analysis of aromatic amino acids has been developed. This method allows qualitative and quantitative evaluation of hemorphins generated by peptic hemoglobin hydrolysis. Using this method, a kinetic study of hemorphins appearance has been undertaken. In this paper, we also evidenced the generation of VV-hemorphin-7 from globin by peritoneal macrophages. In regard to this result, the putative physiological role of hemorphins is discussed. © 1997 John Wiley & Sons, Inc. Biopoly 43: 75-98, 1997
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    Hydrocarbon pasting liquids for improved tyrosinase-based carbon-paste phenol biosensors (1997)
    Weinheim : Wiley-Blackwell
    Electroanalysis 9 (1997), S. 1102-1106 
    Details
    ISSN: 1040-0397
    Keywords: Carbon paste ; Pasting liquid ; Hydrocarbon ; Tyrosinase Phenols ; Biosensor ; FIA ; HPLC ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Short-chain hydrocarbons are used as pasting liquids in carbon-paste tyrosinase amperometric biosensors. The response of the phenolic substrates decreases rapidly upon increasing the chain length of the hydrocarbon binder from C10 to C14, and then it levels off to a size similar to that of the mineral oil biosensor. For example, the dodecane-based enzyme electrode offers a 17.8-fold signal enhancement compared to the mineral-oil one. Such sensitivity enhancements are attributed to the extractive accumulation of the phenolic substrates. The change in the carbon-paste binder influences also the selectivity of the tyrosinase electrode and the Km, app values. Flow-injection analysis yields a detection limit of 6 nM catechol and a relative standard deviation of 2.5% (n = 30). A dual enzyme electrode chromatographic detection, based on the use of different pasting liquids, provides unique characterization of the phenolic substrates. The merits of this strategy are illustrated in connection with a river water sample.
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    Chiral discrimination by ligand-exchange chromatography: A comparison between phenylalaninamide-based stationary and mobile phasesThis work is dedicated to the memory of Professor Emanuel Gil-Av. (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 8 (1996), S. 452-461 
    Details
    ISSN: 0899-0042
    Keywords: enantiomers ; HPLC ; DNS-animo acids ; fluorescence quenching ; ligand-exchange mechanism ; adsorption ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The copper(II) complexes of two new diastereomeric ligands, N2-(R)- and N2-(S)-2′-hydroxypropyl-(S)-phenylalaninamide [(R, S)-1 and (S, S)-1], have been used as additives to the eluent in high-performance liquid chromatography (HPLC) reversed phase for the chiral separation of DNS-amino acids. The aim was that of comparing the separation process obtained by the chiral eluent with that obtained by an analogous bonded stationary phase containing (S)-phenylalaninamide, previously studied [CSP-(S)-Phe-NH2]. The affinity of the ternary complexes for the C18 column was determined by adsorption experiments in HPLC. It was shown that the two systems (chiral eluent, chiral stationary phase) work according to different mechanisms. Ternary complex formation in solution was studied by fluorescence spectroscopy. It was shown that chiral separation with the Cu(II) complexes added to the eluent was determined by the relative affinities of the ternary complexes for the column-stationary phase rather than by their stabilities in solution. With CSP-(S)-Phe-NH2 the separation is accounted for by the relative stabilities of the ternary complexes, which depends mainly on the “allowed” geometry of the complex and on the steric repulsion of the amino acid side chain with the spacer. © 1996 Wiley-Liss, Inc.
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    Application of force field calculations to the prediction of chirally discriminating chromatographic behaviour for β-CDs (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 8 (1996), S. 58-66 
    Details
    ISSN: 0899-0042
    Keywords: molecular mechanics ; HPLC ; chiral separation ; methylphenobarbitone ; hexobarbitone ; ibuprofen ; mandelic acid ; ephedrine ; pseudoephedrine ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: β-Cyclodextrin and its derivatives have been utilised to effect chiral separation in HPLC and CZE, both as stationary phases and mobile phase additives. The basis of the method is assumed to depend upon the formation of inclusion complexes of differing stabilities between enantiomeric analytes and the cyclodextrin, resulting in a differential dynamic distribution between chromatographic phases. In this study, force field calculations have been employed to model the inclusion complexes of enantiomeric brompheniramine, ephedrine, pseudoephedrine, ibuprofen, mandelic acid, methylphenobarbitone, and hexobarbitone with β-cyclodextrin. The resulting values for Δ(ΔH), the difference in enthalpy of complex formation between enantiomeric pairs has been compared with literature chromatographic data to explain the ability of the systems to achieve enantiomeric separations. © 1996 Wiley-Liss, Inc.
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    Use of mathematically enhanced spectral analysis and spectral contrast techniques for the liquid chromatographic and capillary electrophoretic detection and identification of pharmaceutical compounds (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 8 (1996), S. 67-76 
    Details
    ISSN: 0899-0042
    Keywords: spectral analysis ; spectral contrast ; HPLC ; MECC ; peak homogeneity ; peak tracking ; method development ; photodiode array detection ; isomers ; enantiomers ; diastereomers ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of mathematically enhanced ultraviolet/visible (UV/VIS) absorbance spectral analysis and spectral contrast software techniques in high performance liquid chromatography (HPLC) and micellar electrokinetic capillary electrophoresis (MECC) as an aid for the determination of peak homogeneity, identification, and tracking during method development was investigated. Various structurally similar pharmaceutical compounds, and compounds present as either cis/trans isomers, diastereomers, or enantiomers were used as test compounds to probe the limits of this technique. Two tricyclic antidepressants, nortriptyline and imipramine, were employed to study the effects of HPLC mobile phase composition and pH on the ability to identify and track peaks during method development. It was found that method changes altered the spectral matches used for identification, but not enough to cause incorrect peak identification. It was also shown using HPLC that the cis/trans isomers of doxepin and the diastereomers ephedrine and pseudoephedrine could be distinguished.The mathematically enhanced spectral analysis and spectral contrast software techniques were also employed with MECC. Peaks tracking during method development as pH and the concentration of surfactant changes is shown for a separation of various penicillin type antibiotics. It was shown that during chiral MECC (CMECC) analyses ephedrine/pseudoephedrine diastereomers as well as ephedrine enantiomers could be distinguished. The determination of enantiomers is possible in CMECC since enantiomers are eluted as diastereomeric complexes, as opposed to HPLC where they are eluted in their native state. © 1996 Wiley-Liss, Inc.
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    Stereoselective metabolism of two keto-pyrrol analogues of 8-hydroxy-2-dipropyl-aminotetralin by freshly isolated rat hepatocytes (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 8 (1996), S. 264-270 
    Details
    ISSN: 0899-0042
    Keywords: drug development ; enantiomers ; HPLC ; in vitro metabolism ; mass spectrometry ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In vitro metabolism models have been used to determine the relative metabolic stability of novel 2-aminotetralin analogues for the treatment of CNS diseases. Few of these new compounds had been produced as stereochemically pure materials and the achiral analytical techniques, used initially, measured the average metabolic clearance of the two enantiomers of the racemic mixtures.A chiral HPLC assay, using a Chiral AGP column, was developed for two of these racemic analogues and was used to measure the clearance of the enantiomers from suspensions of freshly isolated rat hepatocytes.Robust separations were obtained for both compounds and a number of metabolic products. The enantiomers of only one analogue were subject to different rates of metabolism. The extent of the difference was dependent upon the initial starting concentration of the incubation. The identity of certain metabolites was investigated using LC/MS. The enantioselectivity appears to have arisen from the restricted hydroxylation of one analogue compared to that of the other. © 1996 Wiley-Liss, Inc.
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    Dichloro-, dimethyl-, and chloromethylphenylcarbamate derivatives of cyclodextrins as chiral stationary phases for high-performance liquid chromatography (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 8 (1996), S. 402-407 
    Details
    ISSN: 0899-0042
    Keywords: enantioseparation ; HPLC ; cyclodextrin ; phenylcarbamate ; chiral stationary phase ; optical resolution ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New dichloro-, dimethyl-, and chloromethylphenylcarbamate derivatives of cyclodextrins (CDs) were prepared and their enantiomeric recognition abilities were evaluated as chiral stationary phases (CSPs) in normal phase high-performance liquid chromatography (HPLC). The effects of the type of cyclodextrins, the nature and position of the substituents on the phenyl ring, binding mode and spacer on the chiral recognition were studied in detail. No marked change of chiral recognition abilities was established by reversing the binding side of CDs (i.e., by the narrower [primary] opening of the cone-shaped CD to silica gel with the wider [secondary] opening sides). This result indirectly proves the previously drawn conclusion about the minor role of inclusion phenomena in chiral recognition in this case. Nevertheless, chiral recognition of these CSPs toward some compounds critically depends on the type of CDs used. All CD derivatives described in this study show rather low enantiomeric resolving abilities compared with corresponding polysaccharide (cellulose and amylose) derivatives, although very high enantioselectivity of separation was observed for a few compounds, such as racemic flavanone and cyclopropanedicarboxilic acid dianilide. © 1996 Wiley-Liss, Inc.
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    The use of High-Performance Liquid Chromatography for the Speciation of Organotin Compounds (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 10 (1996), S. 339-362 
    Details
    ISSN: 0268-2605
    Keywords: review ; high-performance liquid chromatography ; HPLC ; organotin ; tributyltin ; speciation ; marine environment ; antifouling paints ; environmental pollution ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This review of the use of high-performance liquid chromatography (HPLC) for the speciation of organotin compounds which are primarily of significance in the marine environment is divided into sections on the basis of the different HPLC modes of separation. However, it should be noted that such a classification does not exist in reality. For instance, in an ion-pair reversed-phase system the separation mechanism for the ionic solutes may be ion-pair partitioning, or ion exchange, or both. The relevant practical information (e.g. column type, mobile phase, method of detection and detection limit) is presented in tabular form. A brief overview of the reported detection methods is included, because the delay in development of an easily interfaced, specific and sensitive detector has hindered the use of HPLC for organotin speciation studies. The literature reviewed covers publications from 1977, the year of the first application of HPLC to organotin speciation, to April 1995.
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    New thermostable systems: structure/property relationships of nadic terminated telechelic fluorine polyimides (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 41 (1996), S. 135-149 
    Details
    ISSN: 0959-8103
    Keywords: telechelic polyimides ; nadimide ; endo/exo isomerization ; NMR ; HPLC ; thermomechanical properties ; α and β transitions ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Polyimides were synthesized by polycondensation of nadic anhydride monoester (NE), hexafluoroisopropylidene-2,2-bis (phthalic acid anhydride) (6HFDA) and Cardo diamine in aprotic/polar medium. After examining the microstructure and the composition of systems with a polymerization index n̄ = 2.075 and 5.18 by high performance liquid chromatography (HPLC) and nuclear magnetic resonance (NMR) spectroscopy (1H and 13C), their thermomechanical properties were investigated. The rheology curves obtained in the temperature range 50-400°C showed the presence of an α transition (glass transition temperature Tg) and a sub-glass β transition. The temperature of the maximum of the loss modulus G″ of these two transitions varied in the domain of molar mass M̄n studied.The effect of endo/exo isomerization of the nadimide extremities on the values of the glass transition temperature has also been shown. When the percentage of exo isomer of a given polymer increased, the glass transition temperature Tg increased by 50°C.
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    Silicalite as a stationary phase for HPLC (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 691-695 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; Molecular sieve ; Cis-trans isomers ; Phenols ; Selectivity ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A molecular sieve known as Silicalite was used as the column packing for HPLC. Silicalite contains channels (or cavities) approximately 6 Å in diameter but, unlike most other molecular sieves, Silicalite is hydrophobic. The retention times of methyl ketones and substituted phenols containing n-alkyl groups increase with increasing chain length of the substituent. However, phenols with very bulky substituents appear to be excluded from the Silicalite channels and elute very quickly. Excellent separations were obtained for a number of compounds with only slight differences in chemical structure. These include phenol isomers with a primary- or secondary alkyl group, position isomers of substituted phenols, and aliphatic cis-trans isomers.
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    On-line supercritical fluid extraction and high performance liquid chromatography for determination of triazine compounds in soil (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 700-702 
    Details
    ISSN: 0935-6304
    Keywords: Supercritical fluid extraction, SFE ; HPLC ; On-line coupling ; Triazines ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/jhrc.1240191211
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    A new approach in exciton-coupled circular dichroism (ECCD) - insertion of an auxiliary stereogenic centerDr. Nina Berova is on leave from the Bulgarian Acadamy of Sciences, Sofia 1113, Bulgaria. (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 7 (1995), S. 128-135 
    Details
    ISSN: 0899-0042
    Keywords: allene ; absolute configuration ; chirality ; method ; synthesis ; resolution ; chromophore ; HPLC ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: There are cases in which exciton coupling between two chromophores does not occur because the two electric transition moments which should interact are coplanar. This is seen with cyclohexane-1,4-diols (both ee or ea) and a wide variety of 3-hydroxy carotenoids, 3-hydroxyretinoids, etc. A general approach to deal with such cases is to acylate one of the hydroxyl groups with a chiral allenic acid substituted with a suitable chromophore, e.g., CHROM—CH=C=CH-COOH. The allenic bond introduces a 90° twist at the italicized central carbon so that the allenic CHROM now couples with the second chromophore. This concept of introducing an auxiliary allenic center should be of general applicability in other similar cases. © 1995 Wiley-Liss, Inc.
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    Stereochemical aspects of the hydration of trans-anethole epoxide in the rat (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 7 (1995), S. 278-284 
    Details
    ISSN: 0899-0042
    Keywords: trans-anethole ; anethole epoxide ; anethole diol ; camphanyl esters ; HPLC ; chiral selective metabolism ; cytosolic epoxide hydrolase ; microsomal epoxide hydrolase ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Racemic trans-anethole epoxide [1-(4′-methoxyphenyl)-propane-1,2-oxide] was incubated with water, buffers, and rat liver microsomes and cytosol and the stereochemistry of the diols produced was determined by HPLC as their dicamphanyl esters. The diol metabolites were isolated by HPLC from the urine of rats administered [1′-14C] trans-anethole and their stereochemistry determined after derivatization to their camphanyl esters. The stereochemical course of the metabolism of trans-anethole by rat liver microsomes and cytosol is discussed. © 1995 Wiley-Liss, Inc.
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    Chromatographic properties of composite chiral stationary phases based on cellulose derivatives (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 7 (1995), S. 425-433 
    Details
    ISSN: 0899-0042
    Keywords: racemate ; enantiomer ; HPLC ; elution order ; drugs ; agrochemicals ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chiral stationary phases (CSPs) prepared by mixing together two different cellulose derivatives, before or after being coated on macroporous silica gel, were developed in order to determine the mutual influence of two different polymers on global chiral recognition capacity. The chromatographic properties of these CSPs were evaluated using a wide range of racemic test solutes. The mixing method does not significantly affect the enantioselectivities. The composite CSPs obtained by cocoating of two different cellulose derivatives on silica generally exhibit chiral recognition capacities intermediate between those of the two individual phases, and thus broadening the application range of a single column. These results indicate that the simultaneous coating of two different cellulose derivatives does not significantly alter the optical resolution power of each chiral material and are discussed in relationship with the supramolecular structure of the polymeric stationary phases. © 1995 Wiley-Liss, Inc.
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    Synthesis of (+)-(R)- and (-)-(S)-trans-8-hydroxy-2-[N-n-propyl-N-(3′-iodo-2′-propenyl)] aminotetralin: New 5-HT1A receptor ligands (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 7 (1995), S. 452-458 
    Details
    ISSN: 0899-0042
    Keywords: optical column ; HPLC ; diastereoisomer ; 125I ; radioligands ; 8-OH-DPAT ; serotonin receptor ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (R,S)-trans-8-Hydroxy-2-[N-n-propyl-N-(3′-iodo-2′-propenyl)amino]tetralin 7, a new radioiodinated ligand based on 8-OH-DPAT, was reported as a potential ligand for 5-HT1A receptors. The optically active (+)-(R)- and (-)-(S)-7 were prepared to investigate the stereoselectivity of (R,S)-7. Racemic intermediate 8-methoxy-2-N-n-propyltetralin was reacted with the acyl chloride of (-)-(R)-O-methylmandelic acid to form a mixture of (S,R)- and (R,R)-diastereoisomers, which were separated by flash column chromatography. After removing the N-acyl group from the diastereoisomers, the desired (+)-(R)-or (-)-(S)-7 was obtained by adding an N-iodopropenyl group. In vitro homogenate binding studies showed the stereoselectivity of this new compound for 5-HT1A receptors. (+)-(R)-7 isomer displayed 100-fold higher affinity than the (-)-(S)-7 isomer. Biochemical study indicated that (+)-(R)-7 potently inhibited forskolin-stimulated adenylyl cyclase activity in hippocampal membranes (Emax and EC50 were 24.5% and 5.4 nM, respectively), while (-)-(S)-7 showed no effect at 1 μM. The radioiodinated (+)-(R)- and (-)-(S)-[125I]7 were confirmed by coelution with the resolved unlabeled compound on HPLC (reverse phase column PRP-1, acetonitrile/pH 7.0 buffer, 80/20). The active isomer, (+)-(R)-[125I]7, displayed high binding affinity to 5-HT1A receptors (Kd = 0.09 ± 0.02 nM). In contrast, the (-)-(S)-7 isomer displayed a significantly lower affinity to the 5-HT1A receptor (Kd 〉 10 nM). Thus, (+)-(R)-[125I]trans-8-OH-PIPAT, (+)-(R)-7, an iodinated stereoselective 5-HT1A receptor agonist, is potentially useful for study of in vivo and in vitro function and pharmacology of 5-HT1A receptors in the central nervous system. © 1995 Wiley-Liss, Inc.
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    A new procedure for the speciation of mercury in water based on the transformation of mercury (II) and methylmercury (II) into stable acetylides followed by HPLC analysis (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 9 (1995), S. 713-718 
    Details
    ISSN: 0268-2605
    Keywords: mercury ; methylmercury ; mercury acetylides ; speciation ; HPLC ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Conversion of mercury(II) and methylmercury(II) species dissolved in water into di(phenylethynyl)mercury and methyl(phenylethynyl) mercury takes place in satisfactory yield under alkaline conditions by stirring the aqueous solution with phenylacetylene at room temperature. Mercury speciation is simply obtained by HPLC analysis of the two organometallic species. The presence of heavy metals such as copper(II), zinc(II), cadmium(II) and lead(II) in concentrations 10000 times higher than mercury is tolerated, while little interference is displayed by humic acids and cysteine. Seawater samples can also be analysed following a properly adapted procedure.
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    URL: http://dx.doi.org/10.1002/aoc.590090810
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    Monodisperse polymer beads as packing material for high-performance liquid chromatography. Preparation of macroporous poly(2,3-epoxypropyl vinylbenzyl ether-co-divinylbenzene) beads, their properties, and application to HPLC separations (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2639-2646 
    Details
    ISSN: 0887-624X
    Keywords: monodisperse beads ; 2,3-epoxypropyl vinylbenzyl ether ; divinylbenzene ; copolymers ; macroporous ; chromatography ; HPLC ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In search for HPLC separation media with new surface chemistries, a styrene-based monomer, 2,3-epoxypropyl vinylbenzyl ether, containing reactive epoxide groups has been syn-thesized and copolymerized with divinylbenzene in a suspension polymerization. The process involves the use of size monodisperse particles that are swollen with monomer and then polymerized in the presence of a porogenic diluent consisting of a mixture of 4-methyl-2-pentanol and octane. The effect of concentration of divinylbenzene on the pore size dis-tribution and the specific surface area of the resulting uniformly sized porous poly(2,3-epoxypropyl vinylbenzyl ether-co-divinylbenzene) beads has been studied. The epoxide groups of the copolymer have been hydrolyzed and the beads used for reversed-phase chro-matography of both small molecules and proteins to show the effect of hydrophobicity of the matrix on the separation properties. Reversed-phase chromatography of alkylbenzenes follows the expected pattern while for proteins the hydrolyzed beads with the highest content of the crosslinking monomer exhibit a remarkable deviation from the predicted retention characteristics. © 1995 John Wiley & Sons, Inc.
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    URL: http://dx.doi.org/10.1002/pola.1995.080331510
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    Separation of lipid classes from plant tissues by high performance liquid chromatography on chemically bonded stationary phases (1995)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 97-100 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; Gradient elution ; Cyano bonded phase ; Polymerized vinyl alcohol bonded phase ; Plant tissue ; Potato ; Lipid classes ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The wide range of lipid classes found in plant tissues, including simple lipids, glycolipids, and phospholipids, have been resolved by gradient high performance liquid chromatography with evaporative light-scattering detection. The lipids from potato tubers were used to optimize the separations. Adsorption chromatography with silica gel gave disappointing results for the plant glycolipids. Much better separations were obtained with chemically bonded stationary phases, e.g. those with propionitrile or polymeric vinyl alcohol as the functional moiety. With careful calibration, good reproducibility was possible. Only highly acidic lipids such as phosphatidylserine still present some problems.
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    Correlation between structure of dihydropyridine calcium antagonists and their retention behavior and enantioseparation on the β-cyclodextrin stationary phase in HPLC (1995)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 597-601 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; Chiral separation ; β-Cyclodextrin ; Molecular modeling ; Calcium antagonists ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chromatographic data for five dihydropyridine calcium antagonists (CAs) were obtained on β-cyclodextrin column in the reversed phase HPLC. Interaction energies of solute-cyclodextrin complexes formed by docking of different parts of the CAs' molecules into the cyclodextrin cavity were calculated. Results from the HPLC experiments and molecular modeling were compared. It was found that several types of inclusion complexes are energetically possible and contribute to the retention simultaneously. Only certain inclusion complex are assumed to be responsible for enantioseparation of CAs. Nevertheless molecular modeling studies are a useful tool for explaining the enantioselectivity and predicting the elution order of enantiomers.
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    Applications of reversed-phase high performance liquid chromatography using enhanced-fluidity liquid mobile phases (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Microcolumn Separations 7 (1995), S. 477-483 
    Details
    ISSN: 1040-7685
    Keywords: HPLC ; enhanced-fluidity ; viscosity ; pressure drop ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enhanced-fluidity liquid mobile phases (methanol/H2O/CO2) were used as eluents in reversed-phase HPLC. The low pressure drop across the column allowed serial connection of micro-scale columns to achieve the efficient separation of a coal tar sample. Other applications such as the separation of fat soluble vitamins and probucol and related compounds are shown. © 1995 John Wiley & Sons, Inc.
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    Relationship of sidechain hydrophobicity and α-helical propensity on the stability of the single-stranded amphipathic α-helix (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Peptide Science 1 (1995), S. 319-329 
    Details
    ISSN: 1075-2617
    Keywords: -α-helix ; α-helical propensity ; hydrophobicity ; HPLC ; thermal stability ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The aim of the present investigation is to determine the effect of α-helical propensity and sidechain hydrophobicity on the stability of amphipathic α-helices. Accordingly, a series of 18-residue amphipathic α-helical peptides has been synthesized as a model system where all 20 amino acid residues were substituted on the hydrophobic face of the amphipathic α-helix. In these experiments, all three parameters (sidechain hydrophobicity, α-helical propensity and helix stability) were measured on the same set of peptide analogues. For these peptide analogues that differ by only one amino acid residue, there was a 0.96 kcal/mole difference in α-helical propensity between the most (Ala) and the least (Gly) α-helical analogue, a 12.1-minute difference between the most (Phe) and the least (Asp) retentive analogue on the reversed-phase column, and a 32.3°C difference in melting temperatures between the most (Leu) and the least (Asp) stable analogue. The results show that the hydrophobicity and α-helical propensity of an amino acid sidechain are not correlated with each other, but each contributes to the stability of the amphipathic α-helix. More importantly, the combined effects of α-helical propensity and sidechain hydrophobicity at a ratio of about 2:1 had optimal correlation with α-helix stability. These results suggest that both α-helical propensity and sidechain hydrophobicity should be taken into consideration in the design of α-helical proteins with the desired stability.
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    URL: http://dx.doi.org/10.1002/psc.310010507
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    Tris(phenylcarbamate) derivatives of amylopectin as chiral stationcoes in HPLC (1995)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 389-391 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; Optical resolution ; Chiral phase ; Substituted amylopectin tris(phenylcarbamate) derivatives ; Benzodiazepines ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/jhrc.1240180615
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    An improved version of an old fluorocarbinol chiral stationary phase (1995)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 353-358 
    Details
    ISSN: 0935-6304
    Keywords: Chiral stationary phase ; Fluorocarbinol ; HPLC ; Enantiomeric separation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A chiral stationary phase (CSP) derived from anthrone is quite effective for the chromatographic resolution of the enantiomers of a wide variety of compounds. Denoted CSP 4, the phase is a chiral 2,2,2-trifluoro-1-(9-anthryl)ethanol tethered to silica by an elevencarbon-atom chain at the 10-position of the anthryl ring. CSP 4 typically provides greater enantioselectivity than its fluoroalcohol predecessor and is synthetically much more accessible.
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    On-Line coupling of supercritical fluid extraction with high performance liquid chromatography (1995)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 472-476 
    Details
    ISSN: 0935-6304
    Keywords: Supercritical fluid extraction, SFE ; HPLC ; On-line coupling ; PAHs ; Linear alkylbenzene sulfonate ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Supercritical fluid extraction was coupled directly with high performance liquid chromatograph. The system was evaluated for direct injection of supercritical CO2 and modified supercritical CO2 at high pressure and temperature onto a HPLC system with varying mobile phase compositions and flow rates. Injection of 9 μL supercritical CO2 onto the HPLC using methanol/water mobile phases from 100% methanol to 80% with a flow of 1.0 mL/min did not adversely affect the baseline of UV detector. However at higher percentages of water, CO2 solubility in the mobile phase decreased and caused baseline interferences on the UV detector. At higher HPLC mobile phase flow rates, supercritical CO2 was injected to higher percentages of water without any effect on the UV baseline. Also, increasing the extraction pressure or modifier concentration did not change the results. Separations of polynuclear aromatic hydrocarbons and linear alkenebenzene sulfonate test mixtures were obtained using on-line SFE/HPLC interfaced system.
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    Determination of phytic acid and its degradation products in extracts of rape seeds and rapeseed meal (1995)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 267-268 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; Rape seeds ; Rapeseed meal ; Phytic acid ; Inositol phosphates ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/jhrc.1240180413
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    Special selectivity of phenolic derivatives on a novel poly(4-methyl-5-vinylthiazole) stationary phase by reversed phase liquid chromatography (1995)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 671-674 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; Reversed phase ; 4-Methyl-5-vinylthiazole ; Phenolic derivatives ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Supercritical fluid extraction of furanocoumarins from the fruits of Archangelica off. Hoffm (1995)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 781-783 
    Details
    ISSN: 0935-6304
    Keywords: Supercritical Fluid Extraction ; HPLC ; Furanocoumarins ; Isolation from plants ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/jhrc.1240181213
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    Vergleich von in Lösung und mit HPLC bestimmten Bildungsenthalpien über Wasserstoffbrücken gebundener Wirt-Gast-KomplexeQuantitative Host-Guest Complexation Studies Using Chemically Bonded Stationary Phases, 2. Mitteilung. - 1. Mitteilung: [1]. Diese Arbeit wurde von den National Institutes of Health gefördert (GM38010). (1995)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 107 (1995), S. 2589-2592 
    Details
    ISSN: 0044-8249
    Keywords: Heterocyclen ; HPLC ; Supramolekulare Chemie ; Wasserstoffbrücken ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/ange.19951072119
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    A Comparison of Enthalpies of Formation in Solution and Enthalpies for HPLC Retention for Hydrogen-Bonded Host - Guest ComplexesQunatitative Host-Guest Complexation Studies Using Chemically Bonded Stationary Phases, Part 2, Part 1: Ref. [2]. This work was supported by the National Institutes of Health (GM38010). (1995)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 34 (1995), S. 2404-2406 
    Details
    ISSN: 0570-0833
    Keywords: heterocycles ; HPLC ; hydrogen bonding ; supramolecular chemistry ; thermodynamics ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/anie.199524041
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    Differential effects of neuropeptides on the distal and mid-tubules of the house cricket (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 29 (1995), S. 11-23 
    Details
    ISSN: 0739-4462
    Keywords: cricket ; HPLC ; neuropeptide ; diuretic ; antidiuretic ; Malpighian tubule ; fluid secretion ; Mas-DP1 ; achetakinin ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In the Malpighian tubules of Acheta, the distal and middle segments are functionally and morphologically quite distinct (Spring and Kim, Mol Comp Physiol 12:130-145, 1993). Furthermore, they respond quite differently to corpora cardiaca (CC) homogenates, dibutyryl cAMP, and A23187 (Kim and Spring, J Insect Physiol 38:373-381, 1992). In this study we compared secretion by these two regions in response to Acheta and Romalea CC extracts, synthetic Manduca sexta diuretic peptide (Mas-DP1), and the family of synthetic myotropic peptides, the achetakinins, isolated from Acheta. Both Acheta and Romalea CC extracts had opposite effects on the two regions: mid-tubule secretion increased 3-fold whereas secretion by the distal segment declined 75-80%. Mas-DP1 increased secretion by the mid-tubule more than 3-fold and had no effect on the distal segment. All of the achetakinins decreased secretion by the distal tubule, with achetakinin 1 being least effective (55% inhibition) and achetakinin 5 being most effective (75% inhibition). Achetakinins 1 and 2 increased midtubule secretion by 3.7- and 3.3-fold, respectively, whereas the others had no effect on this region. Regarding HPLC fractions of CC extracts, in general the more hydrophilic fractions inhibited secretion by both distal and mid-tubules. The more hydrophobic fractions were nearly uniformly stimulatory when applied to the mid-tubule, and either inhibited secretion or had no effect on the distal region. The possible interpretations of these data and the implications towards future research are discussed. © 1995 Wiley-Liss, Inc.
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    Characterization of the juvenile hormone epoxide hydrolase (JHEH) and juvenile hormone diol phosphotransferase (JHDPT) from Manduca sexta Malpighian tubules (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 30 (1995), S. 255-270 
    Details
    ISSN: 0739-4462
    Keywords: juvenile hormone kinase ; tritiation ; HPLC ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Juvenile hormone epoxide hydrolase (JHEH) and juvenile hormone diol phosphotransferase (JHDPT) were characterized from the Malpighian tubules of day 1 fifth instar Manduca sexta. An improved RP-HPLC assay is described for the major metabolites of (10R, 11S) juvenile hormone I: diol, acid, aciddiol, and diol-phosphate. JHEH is strictly associated with membrane fractions, while JHDPT is cytosolic. JHEH may be solubilized in active form by the nonionic detergents Thesit or MEGA-8. Separation of Malpighian tubule cytosol proteins using preparative isoelectric focusing yields two zones which contain JHDPT activity, at pl 4.8-5.1 and 6.8-8.2. The partially purified JHDPT from either zone requires both ATP and Mg2+ for activity, so this enzyme may be formally called either ATP:juvenile hormone diol phosphotransferase or juvenile hormone diol kinase (EC 2.1.7.3.). Metabolites more polar than JH I aciddiol and JH I diol-phosphate are generated in vivo from either [3H]JH I or [3H]JH I diol. © 1995 Wiley-Liss, Inc.
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    Stereoselectivity of the in vitro metabolism of thalidomideDedicated to Professor Dr. Siegfried Ebel, Würzburg, on the occasion of his 60th birthday. (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 6 (1994), S. 221-224 
    Details
    ISSN: 0899-0042
    Keywords: thalidomide enantiomers ; HPLC ; hydroxylated metabolites ; mass spectrometry ; EM 12 ; in vitro metabolism ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The stereoselective metabolism of the former sedative thalidomide and the metabolism of its analogue EM 12 were studied in vitro with liver homogenates. In our study we focused on hydroxylated nonhydrolyzed metabolites of thalidomide. An analytical HPLC method was developed to determine these metabolites directly. The investigations showed a highly stereoselective biotransformation of thalidomide. 5-Hydroxy thalidomide was preferentially formed by (-)-(S)-thalidomide, whereas (+)-(R)-thalidomide was metabolized to two hitherto unknown compounds (Met A and B). Mass spectrometry of these metabolites Met A and B indicated that oxidation or hydroxylation took place in the glutarimide moiety. Biotransformation studies with the more stable thalidomide analogue EM 12 revealed four new metabolites (Met C—F) whose quantities differed in the selected liver homogenate. © 1994 Wiley-Liss, Inc.
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    Molecular modelling of the inclusion complexes between β-cyclodextrin and (R)/(S)-methylphenobarbitone and its application to HPLC (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 6 (1994), S. 239-244 
    Details
    ISSN: 0899-0042
    Keywords: HPLC ; reverse-phase additive ; β-cyclodextrin ; methylphenobarbitone ; molecular mechanics ; complex stability ; chiral separation ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Molecular modelling of β-cyclodextrin and optimisation of its potential energy suggests that a favoured conformation is that distorted from a symmetrical torus. The inclusion of water molecules into the torus cavity simulates the increased stability in an aqueous solvent. Complexes of β-cyclodextrin with (R)- and (S)-enantiomers of methylphenobarbitone have been modelled and energetically optimised by the application of molecular mechanics. The simulations suggests that the guest molecules adopt an orientation in which the phenyl ring is projected into the torus cavity, with in each case the plane of the ring parallel to a longer axis of the distorted torus and slightly displaced from the axis through the torus cavity. It is suggested that the asymmetry in the macrocyclic ring contributes to chiral recognition as a result of additional discriminatory binding to the barbiturate ring residue of each enantiomer, which occupy different 3D geometries. The enantiomers form complexes of different minimum potential energies. The resulting difference in complex stability can be related to the behaviour of β-cyclodextrin, as a mobile phase additive in reverse-phase HPLC to effect chiral separation of rac-medthylphenobarbitone during chromatography. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/chir.530060405
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    A preliminary pharmacokinetic study of the enantiomers of the terfenadine acid metabolite in humans (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 6 (1994), S. 479-483 
    Details
    ISSN: 0899-0042
    Keywords: terfenadine metabolite ; enantiomer separation ; HPLC ; pharmacokinetics ; humans ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A stereoselective and sensitive achiral/chiral method for the determination of terfenadine acid metabolite in human plasma was developed. The metabolite was separated and quantitated using an achiral chromatographic procedure with a cyano column. The mobile phase was 1 mM sodium acetate buffer (pH 4.0) and acetonitrile (25:75% v/v) at a flow rate of 2 ml/min, at ambient temperature. The stereospecific resolution was accomplished using a chiral-AGP column and a mobile phase consisting of sodium acetate (0.01 M): methanol (98.7:1.3% v/v), and 20 mM di-n-butylamine at a flow rate of 1.2 ml/min. The column temperature was maintained at 32°C. The eluent was monitored at 230 nm (excitation) and 300 nm (emission) with a cut-off filter at 270 nm. This assay was used for a pharmacokinetic study in five subjects after administration of a single dose of 60 mg of terfenadine. The t½ values of the two enantiomers were similar, but the AUC values of the (+)-enantiomer were 2.05-2.35 times higher than those of (-)-enantiomer. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/chir.530060606
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    Determination of the enantiomers of mianserin, desmethylmianserin, and 8-hydroxymianserin in the plasma and urine of mianserin-treated patients (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 6 (1994), S. 555-563 
    Details
    ISSN: 0899-0042
    Keywords: mianserin ; enantiomer ; metabolism ; human plasma ; urine ; HPLC ; CYP2D6 ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An HPLC method is presented which allows the measurement in the same run of the enantiomers of mianserin, desmethylmianserin, and 8-hydroxymianserin in plasma and urine of mianserin-treated patients. Limits of quantitation for the (S)- and (R)- enantiomers of mianserin and desmethylmianserin were 4 and 2.5 ng/ml, respectively, in plasma, and for the (S)- and (R)-enantiomers of mianserin, desmethylmianserin, and 8-hydroxymianserin 5, 2.5, and 5 ng/ml, respectively, in urine. The measured ratios of (S)-mianserin/(R)-mianserin and (S)-desmethylmianserin/(R)-desmethylmianserin in the plasmas of 10 mianserin-treated patients, all extensive metabolizers of debrisoquine as determined by CYP2D6 genotyping, varied, respectively, from 1.0 to 4.06 and from 0.19 to 0.64. As the enantiomers of mianserin differ in their pharmacological profile, these results could partially explain why, until now, no consistent relationship has been established between the therapeutic response and total [(S) + (R)] plasma levels of this antidepressant. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/chir.530060708
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    Assignment of absolute configuration to an improved enantioselective naproxen selector (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 6 (1994), S. 615-622 
    Details
    ISSN: 0899-0042
    Keywords: absolute configuration ; chiral stationary phase ; enantiomer ; chiral recognition ; NSAID ; HPLC ; NMR ; CD ; X-ray ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Assignment of absolute configuration to a recently developed chiral selector useful in the separation of the underivatized enantiomers of naproxen and other nonsteroidal anti-inflammatory drugs (NSAIDs) is described. Circular dichroism, 1H NMR, and X-ray diffraction have been used to confirm the original assignment which was based solely upon elution orders from HPLC chiral stationary phases. All of these techniques agree in the assignment of the (S,S) absolute configuration to the enantiomer of the chiral selector which associates preferentially with (S)-naproxen. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/chir.530060803
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    Why are random copolymers of styrene and acrylic acid effective as stabilizers for nonaqueous dispersion polymerization of styrene? (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 571-574 
    Details
    ISSN: 0887-624X
    Keywords: styrene-acrylic acid random copolymers ; copolymer composition distribution ; nonaqueous dispersion polymerization ; HPLC ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1994.080320318
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    Separation of fuels, heavy fractions, and crude oils into compound classes: A review (1994)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 197-202 
    Details
    ISSN: 0935-6304
    Keywords: GC and GC-MS ; HPLC ; SFC ; TLC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Practically all the conventional chromatographic techniques are used in the characterization of the highly complex mixtures of organic compounds occurring in fuels, heavy fractions, and crude oils. This paper surveys the techniques employed for class determination, preparative fractionation of the main classes, and determination of subgroups after class fractionation.
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    Complete separation of the geometical isomers of linolenic acid by high performance liquid chromatography with a silver ion columnPresented in part at the AOCS short course ‘New Trends in Lipid and Lipoprotein Analysis’ in La Grande Motte, France, September 1993. (1994)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 321-324 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; Silver ion column ; cis Fatty acid ; trans Fatty acid ; Phenacyl derivatives ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method has been developed for separation of linolenic acid and its seven isomers by HPLC on a silver-ion-loaded column. The standard 18:3 isomers, isolated from a heated linseed oil or prepared by isomerization of linolenic acid, were converted into phenacyl esters and detected by UV at 238 nm. The use of low temperature (10 °C) combined with a gradient of dichloromethane and methanol enabled separation of all the cis/trans isomers. The peaks were identified by comparison of ECL values with those of a standard mixture, by chromatographing collected HPLC fractions on a polar GC column. HPLC quantification was compared with GC analysis. There was satisfactory agreement between the tow methods. This method could be used for seperation, collection and quantification of 18:3 fatty acids with trans double bonds in different oils and foods.
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    URL: http://dx.doi.org/10.1002/jhrc.1240170508
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    Reproducibility of the determination of caffeine in coffee by micellar electrokinetic capillary chromatography (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Microcolumn Separations 6 (1994), S. 5-10 
    Details
    ISSN: 1040-7685
    Keywords: caffeine ; coffee ; micellar electrokinetic capillary chromatography (MECC) ; reproducibility ; HPLC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Samples of regular and decaffeinated varieties of green coffee beans, instant coffee, and “roast & grind” coffee have been examined by micellar electrokinetic capillary chromatography (MECC). The separation conditions affecting the reproducibility of the determination of caffeine in these samples are presented. Sodium dodecyl sulfate (SDS) and cetyltrimethylammonium chloride (CTAC) Were employed to demonstrate the role of the surfactant system in reproducibility. The use of NaOH and HCl was explored for column rinsing to enhance the stability of the electroosmotic flow. The levels of caffeine ranged from 3.95% (by weight) for regular coffee to 0.07% for decaffeinated coffee. The relative standard deviation (RSD) for the migration time of the peak corresponding to caffeine in coffee samples was 0.74%. The RSDs for the peak areas and heights were 1.04 and 2.07%, respectively. The results of the quantitation of caffeine by MECC are compared to levels determined by high-performance liquid chromatography (HPLC).
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    URL: http://dx.doi.org/10.1002/mcs.1220060103
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    Rapid separations of fullerenes by donor - acceptor liquid and supercritical fluid chromatography (1994)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 104-106 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; SFC ; Rapid analysis ; Donor - acceptor chromatography ; Acceptor bonded phases ; C60 fullerene ; C70 fullerene ; Higher fullerenes ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jhrc.1240170214
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    Analysis of sorbitan ester surfactants. Part I: High performance liquid chromatography (1994)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 15-19 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; Surfactants ; Sorbitan esters ; Span ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sorbitan ester surfactants are very complicated mixtures. An improved and simple reversed phase high performance liquid chroma tographic (HPLC) method employing a C18 column has been developed for the rapid separation of sorbitan ester surfactants and the quantitative determination of the distribution of sorbitan mono-, di-, tri-, and tetraester fractions. The sorbitan ester distribution of the six Span and Arlacel surfactants studied was calculated using relative response factors obtained from analysis of pure glycerides of fatty acids. The effects of mobile phase composition on the accuracy and reliability of the distribution values calculated for the sorbitan esters were investigated.
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    Determination of the purity of synthetic peptides by capillary electrophoresis, high performance liquid chromatography, and laser desorption mass spectrometry (1994)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 102-103 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; Capillary electrophoresis (CE) ; Laser desorption mass spectrometry ; Synthetic peptides ; Purity determination ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/jhrc.1240170213
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    Reversed phase HPLC determination of titanium(IV) and iron(III) with sodium 1,2-dihydroxybenzene-3,5-disulfonic acid (1994)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 770-772 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; Titanium(IV) ; Iron(III) ; Sodium 1,2-dihydroxybenzene-3,5-disulfonic acid (Tiron) ; River water analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A highly sensitive method has been developed for the determination of titanium(IV) and iron(III) by ion-pair reversed phase liquid chromatography using sodium 1,2-dihydroxybenzene-3,5-disulfonic acid (Tiron) as a precolumn chelating reagent. The metal - Tiron chelates were separated on a C18 (ODS) column; the mobile phase was a 2:8 (v/v) mixture of acetonitrile and acetate buffer (0.04 mol/L, pH 6.2) containing 2.0 × 10-3 mol/L Tiron, 0.04 mol/L tetrabutylammonium bromide, and 0.1 mol/L potassium nitrate. The detection limits for titanium(IV) and iron(III) are 0.5 and 2.0 μg/L, respectively. The method has been applied to the simultaneous determination of titanium(IV) and iron(III) in river water samples and has furnished highly precise results.
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    Chiral stationary phase design: A study in optimization (1994)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 629-633 
    Details
    ISSN: 0935-6304
    Keywords: Chiral stationary phase ; Chiral separations ; HPLC ; N(1-Naphthyl)leucine ; N(5-Acenaphthyl)leucine ; Polysiloxane ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A π-basic, brush-type chiral stationary phase (CSP) derived from (S)-N-(1-naphthyl)leucine undecenyl ester has been shown to effectively separate the enantiomers of a broad array of π-acidic analytes. Armed with a mechanistic hypothesis as to how this CSP differentiates between the enantiomers of π-acidic derivatives of α-amino acids, the structure of this CSP was modified in a series of steps, each intended to enhance the enantioselectivity of the CSP. Specifically, brush-type CSPs were prepared from N-(5-naphthyl)leucine di-n-propyl amide and from N-(5-acenaphthyl)leucine di-n-propyl amide. The latter selector was also incorporated into a polysiloxane, then coated and bonded to silica. The rationale for each of the structural changes, and its effect on the enantioselectivity of the resulting CSP is described.
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    Identification of the main flavonoids by use of chromatographic, electrophoretic, and ‘on-line’ spectral data (1994)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 616-618 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; MEKC ; Diode-array detection ; Flavonoid analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jhrc.1240170812
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    Determination of lysinoalanine by high performance liquid chromatography (1994)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 827-830 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; Fluorimetric detection ; UV detection ; Proteins of animal origin ; Lysinoalanine ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This work suggests an HPLC method for qualitative and quantitative determination of Nε(2-amino-2-carboxyethyl)-L-lysine (LAL). LAL was released from total hydrolysates of various proteins of animal origin and derivatized with dansyl chloride. The performance of two different columns, Spherisorb 3S TG and μ-Bondapack C18, was compared; better resolution and quantitative response were obtained with the former. The mobile phase was a mixture of 0.01 M phosphate buffer (pH 7) and acetonitrile. Linear response and quantitative repeatability were tested for both detectors used (UV-Vis set at 254 nm; fluorimetric set at λex(max) = 360 nm and λem(max) = 525 nm).For LAL standard the minimum detectable amount was 0.05 ng, whereas for LAL in actual samples the amount was 0.5 ng (40 μg/g of analyzed proteins). Good analytical repeatability was obtained, resulting in CV % of 4.7 and 3.8 for UV and fluorimetric detectors, respectively. LAL recovery was determined using both detectors; the values obtained were 94 % (fluorimetric) and 92 % (UV). Greater noise levels were observed with the fluorimetric detector and its higher sensitivity could not, therefore, be fully utilized. The highest amounts of LAL were found in the casein (2816 μg/g) and cooked albumin (615 μg/g) samples.
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    Biosynthesis, secretion, and immunocytochemistry of trypsin modulating oostatic factor of Aedes aegypti (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 27 (1994), S. 27-38 
    Details
    ISSN: 0739-4462
    Keywords: hormone ; HPLC ; ovary ; antibody ; PAGE ; pulse-chase ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Trypsin modulating oostatic factor (TMOF) was followed by RIA in the ovary of female Aedes aegypti before and after the blood meal. The amount of TMOF in a pair of ovaries from females fed sugar for 3 days or blood for 24 h was low (1.7 ng). Between 24 and 48 h after the blood meal the amount of TMOF in the ovaries rapidly increased and reached a peak of 104 ng at 48 h. The amount of TMOF in the head of a female A. aegypti was very low (0.05 to 0.1 ng) during sugar and blood feeding. Immunocytochemical methodology identified the follicular epithelium as the site of biosynthesis of TMOF in the ovary. Females ovariectomized and fed a blood meal continued to synthesize trypsin for 64 h, whereas intact controls stopped at 40 h, indicating that a factor from the ovary regulates trypsin biosynthesis. Ovaries incubated in vitro with [3H]proline synthesized [pro-3H]TMOF that was identified by HPLC and by anti-TMOF serum. The ovary started to synthesize TMOF in vitro 24 h after the blood meal, and the synthesis reached a peak at 36 h and then declined. The synthesis of TMOF by the ovary is closely correlated with the termination of trypsin biosynthesis in the female mosquito's midgut. Ovaries that were pulsed with [3H]proline for 30 min synthesized [pro-3H]TMOF which was chased into the medium with unlabeled proline, indicating that the hormone is secreted by the ovary. These results indicate that TMOF is a secretory peptide, synthesized by the ovarian follicular epithelium and that it modulates trypsin biosynthesis in the mosquito's gut. © 1994 Wiley-Liss, Inc.
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    Biosynthesis of (10R)-Juvenile hormone III from farnesoic acid by Aedes aegypti ovary (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 27 (1994), S. 11-25 
    Details
    ISSN: 0739-4462
    Keywords: hormone ; HPLC ; gas chromatography ; tissue culture ; methoxyhydrin derivative ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Synthesis of (10R)-juvenile hormone III (JH III) outside the corpora allata (CA) was investigated in female Aedes aegypti. Intact females or ligated abdomens of blood-fed and sugar-fed females synthesized in vivo [12-3H]JH III-like molecules from [12-3H]-methyl farnesoate, indicating that an organ(s) in the female abdomen, other than the CA, converted methyl farnesoate into JH III. To find out the organ(s) that synthesized JH III-like molecules, ovaries, fat bodies, and midguts were incubated in vitro with [12-3H]methyl farnesoate and the synthesis of JH III-like molecules was compared with JH III synthesized by CA. To identify tissue(s) having both farnesoic acid methyl transferase and farnesoate epoxidase, enzymes that convert farnesoic acid into JH III, ovaries, and fat bodies were removed from sugar and blood-fed females and incubated with [12-3H]farnesoic acid. Chemical derivatization by methoxyhydrin formation followed by esterification with (+)-α-methoxy- α-trifluoromethyl phenylacetic (MTPA) acid chloride and reversed phase liquid chromatography identified (10R)-JH III methoxyhydrin (+)-MTPA ester as the sole JH III-like molecule produced in tissue culture incubation of ovaries. Since only (10R)-JH III is produced and not racemic JH III, the oxidation of farnesoic acid must be enzymatically mediated. Ovaries and corpora allata of female A. aegypti also synthesized [3H,14C]JH III from L-[methyl-3H]methionine and [14C]acetate which was characterized by HPLC and gas chromatography. These results suggest that mosquito ovary can synthesize (10R)-JH III from farnesoic acid, and that this tissue synthesizes JH III-like molecules from L-methionine and acetate. © 1994 Wiley-Liss, Inc.
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    Analysis of β-glucans and chitin in a Saccharomyces cerevisiae cell wall mutant using high-performance liquid chromatography (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 1083-1092 
    Details
    ISSN: 0749-503X
    Keywords: Cell wall ; glucan ; chitin ; killer toxin ; HPLC ; S. cerevisiae ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We have previously shown that mutations in the yeast KNR4 gene resulted in pleiotropic cell wall defects, including resistance to killer 9 toxin, elevated osmotic sensitivity to SDS and increased resistance to zymolyase, a (1→3)-β-glucanase. In this report, we further demonstrated that knr4 mutant cells were more permeable to a chromogenic substrate, X-GAL, suggesting that the mutant cell walls were leakier to certain non-permeable molecules. To determine if these defects resulted from structural changes in the cell walls, we analysed the alkali-insoluble cell wall components using HPLC assays developed for this purpose. Comparative analysis using four isogenic strains from a ‘knr4 disrupted’ tetrad demonstrated that mutant cell walls contained much less (1→3)-β-glucan and (1→6)-β-glucan; however, the level of chitin, a minor cell wall component, was found to be five times higher in the mutant strains compared to the wild-type strains. The data suggested that the knr4 mutant cell walls were dramatically weakened, which may explain the pleiotropic cell wall defects.
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    URL: http://dx.doi.org/10.1002/yea.320100810
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    Application of computer to monitoring and control of fermentation process: Microbial conversion of ML-236B Na to pravastatin (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 42 (1993), S. 815-820 
    Details
    ISSN: 0006-3592
    Keywords: pravastatin ; ML236B sodium salt ; computer coupled control system ; HPLC ; on-line monitoring ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An automatic feeding process for microbial hydroxylation of ML236B sodium salt (ML-236B Na; compactin) by Streptomyces carbophilus SANK 62585 was developed. The hydroxylated product, pravastatin sodium salt (pravastatin; trade name Mevalotin), is an inhibitor of 3-hydroxy-3-methyglutaryl-coenzyme A reductase (HMG-CoA reductase) used as cholesterol-lowering drug. The hydroxylation activity of S. carbophilus was induced by the addition of ML236B Na to culture broth but inhibited by high concentration of ML236B Na. In order to obtain high conversion yield, it was necessary to maintain optimum ML236B Na concentration throughout the fermentation by continuous feeding. For this purpose, we developed an on-line monitoring method, which mainly consisted of a cross-flow filtration module, high-performance liquid chromatography (HPLC) analyzer, feed pump, and microcomputer for regulation of ML236B Na concentration. An algorithm for control of ML236B Na feed rate based on feedback and feed-forward control where conversion rate after Δt was estimated by using regression analysis of the five latest values of conversion rate. In a fed-batch culture employing this system, the concentration of ML236B Na was maintained at optimum level during the fermentation and the productivity of pravastatin was increased threefold over that obtained in manual control culture. © 1993 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260420705
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    Stereoselective analysis of ketorolac in human plasma by high-performance liquid chromatography (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 5 (1993), S. 31-35 
    Details
    ISSN: 0899-0042
    Keywords: ketorolac enantiomers ; HPLC ; plasma concentrations ; nonnarcotic analgesic ; nonopiate analgesic ; diastereomers ; nonsteroidal antiinflammatory drugs (NSAIDs) ; stereoselective pharmacokinetics ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A high-performance liquid chromatographic (HPLC) analytical method is described for the quantification of the (R)- and (S)-enantiomers of ketorolac when present together in human plasma. The method involves derivatization with thionyl chloride/(S)-1-phenylethylamine and subsequent reversed-phase chromatography of the diastereomeric (S)-1-phenylethylamides of (R)- and (S)-ketorolac. The method is suitable for the analysis of large numbers of plasma samples and has been applied in this report to a pharmacokinetic study of ketorolac enantiomers upon intramuscular administration of racemic drug to a human subject. The limit of quantification for each enantiomer of ketorolac is 50 ng/ml (signal-to-noise ratio 〉 10). © 1993 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/chir.530050107
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  • 84
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    Stereospecific determination of the in vitro dissolution of modified release formulations of (±)-verapamil (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 5 (1993), S. 443-447 
    Details
    ISSN: 0899-0042
    Keywords: verapamil ; dissolution ; stereospecific ; enantiomer ; HPLC ; in vitro ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The determination of the in vitro dissolution profiles of three different modified-release formulations of (±)-verapamil were determined and compared to a reference (Calan SR). The determination of (±)-verapamil utilized a microwave-facilitated derivatization reaction with an enantiomerically pure reagent followed by measurement of drug by reversed-phase high-performance liquid chromatography (HPLC). The dissolution profile of each of the four modified-release formulations was followed for the first hour in simulated gastric fluid (pH 1.2) and then in simulated intestinal fluid (pH 7.5) for up to a total of 12 h. The resulting dissolution profiles of each modified-release formulation suggested that only one of the three test formulations had a similar dissolution to the Calan SR reference. Interestingly, the (S:R)-enantiomer ratios of two of the test products were significantly different from unity, and the third test product was also significantly different from unity if 4 out of 5 outliers were omitted. It is suggested that dissolution testing of modified-release formulations containing chiral active ingredients must be stereospecific in order to discern whether a drug-excipient interaction occurs. Additionally, it may be suggested that dissolution techniques relying more upon diffusion of medium through the tablet matrix, rather than erosion of the tablet, may accentuate enantiomeric differences in release rates. © 1993 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/chir.530050609
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    Chiral-recognition chromatography of β-blockers on continuous polymer beds with immobilized cellulase as enantioselective protein (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 5 (1993), S. 464-470 
    Details
    ISSN: 0899-0042
    Keywords: continuous bed ; chiral phase ; cellulase ; enantiomers ; HPLC ; β-blockers ; propranolol ; alprenolol ; metoprolol ; labitolol ; practolol ; pindolol ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Columns prepared by coupling cellulase as a chiral selector to silica beads are very efficient for the separation of enantiomers. In this paper we show that continuous polymer beds compete favorably with silica beads as chromatographic supports for such separations. The chiral stationary phase is prepared either by entrapment in and simultaneous covalent linkage of ally1 cellulase to the continuous beds during their preparation or by covalent immobilization of cellulase on an epoxy-activated continuous bed. Enantiomers of β-blockers were separated rapidly and with high resolution. The enantiomers of practolol were thus baseline resolved within 45 sec. The recognition center-or at least part of it - coincides with the active center of the enzyme, since the enantiomers could not be separated in the presence of the competitive enzyme inhibitors cellobiose and D-glucose and the separation was also impaired upon addition of the substrate carboxymethyl cellulose to the eluent. Similar observations have been reported for silica columns derivatized with cellulase. The capacity factor and the separation selectivity could be tuned by the pH and the concentration of the mobile phase, a phosphate buffer. No modifier was required, as is sometimes the case with silica-based supports. The continuous beds give faster enantiomer separations than do columns of silica and are more pH-stable and cost effective to prepare. © 1993 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/chir.530050612
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    Chromatographic resolution of chiral intermediates in β-adrenergic blocker synthesis on chiral stationary phases (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 5 (1993), S. 554-559 
    Details
    ISSN: 0899-0042
    Keywords: HPLC ; chiral stationary phases ; resolution of enantiomers ; β-adrenergic blockers ; alcohols ; acetates ; Chiralcel OB ; Chiralcel OD ; Chiralpak OT(+) ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The enantiomeric purities of optically active intermediates for β-adrenergic blocking agents prepared via enzyme-assisted processes can be determined rapidly and with high accuracy using HPLC on commercially available columns with chiral supports [Chiralcel OD, OB; Chiralpak OT(+)]. The dependence of the resolution parameters on the substitution pattern of both hydroxy compounds and their esters is reported. © 1993 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/chir.530050712
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    Resolution of enantiomers by HPLC on tris(4-alkoxyphenylcarbamate)s of cellulose and amylose (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 5 (1993), S. 616-621 
    Details
    ISSN: 0899-0042
    Keywords: cellulose tris(4-isopropoxyphenylcarbamate) ; cellulose tris(3,5-dimethyl-4-methoxyphenylcarbamate) ; amylose tris(3,5-dimethyl-4-methoxyphenylcarbamate) ; optical resolution ; HPLC ; chiral stationary phase ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ten phenylcarbamate derivatives of cellulose and amylose having alkoxy groups such as ethoxy, isopropoxy, and isobutoxy at 4-position, and methyl groups at 3- and 5-positions and methoxy group at 4-position were synthesized and their chiral recognition abilities as stationary phases for high-performance liquid chromatography were investigated and compared to those with tris(4-methoxyphenylcarbamate)s of cellulose and amylose. In 4-alkoxy derivatives of cellulose, chiral recognition ability increased as the bulkiness of 4-alkoxy groups increased. 4-Isopropoxy and 4-isobutoxy derivatives showed high chiral recognition. On the other hand, chiral discrimination of amylose 4-alkoxy derivatives scarcely depended on the bulkiness of the alkoxy group, and 4-methoxy and 4-isopropoxy derivatives showed high chiral recognition. 3,5-Dimethyl-4-methoxyphenylcarbamates of cellulose and amylose possessed higher chiral recognition ability than the corresponding 4-methoxy derivatives. © 1993 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/chir.530050809
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  • 88
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    Sulfur Compounds. 164 Thermal Polymerization of the Cyclic Seleniumsulfide 1,2-Se2S5 Studied by DSC, HPLC, Raman Spectroscopy, and X-Ray Diffraction (1993)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 1589-1596 
    Details
    ISSN: 0044-2313
    Keywords: Seleniumsulfides ; thermal polymerization ; DSC ; HPLC ; Raman spectroscopy ; X-ray diffraction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Schwefelverbindungen. 164. Thermische Polymerisation des cyclischen Selensulfids 1,2-Se2S5 - eine Untersuchung mittels DSC, HPLC, Ramanspektroskopie und RöntgenbeugungKristallines 1,2-Se2S5 polymerisiert bei 47°C endotherm zu einem kettenförmigen Polymer, das nach Streckung und Extraktion aus helicalen Molekülen ähnlich denen im polymeren Schwefel besteht. Beim Erhitzen zersetzt sich das Polymer bei 84°C exotherm zu einer Mischung aus sieben cyclischen SenS8-n-Molekülen; diese Mischung schmilzt bei 111°C. Wenn das polymere Se2S5 mit CS2 gekocht wird, enstehen primär 1,2-Se2S5, SeS5 und 1,2,3-Se3S5, aber zusätzlich werden SeS7 und 1,2-Se2S6 beobachtet.Diese Ergebnisse sprechen für die Atomfolge -Se—S5—Se- in dem Polymer, dessen Pulverdiagramm, Gitterkonstanten und Ramanspektrum mitgeteilt werden.
    Notes: Solid 1,2-Se2S5 polymerizes endothermically at 47°C to give a linear polymer which after stretching and extraction consists of helical molecules similar to those of polymeric sulfur. Heating of the polymer results in slow exothermic depolymerization at 84°C to give a mixture of seven cyclic SenS8-n molecules which melts at 111°C. When the polymeric Se2S5 is refluxed with CS2 the initial depolymerization Products are 1,2-Se2S5, SeS5 and 1,2,3-Se3S5 but in addition SeS7 and 1,2-Se2S6 are formed. These results indicate the atomic sequence -Se—S5—Se- in the polymer. The powder x-ray diffraction pattern and Raman spectrum of the polymer as well as its lattice parameters are reported and the Probable mechanism of its depolymerization is discussed.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19936190914
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    Sequential analysis of polyesters by stepwise chemical degradation: Application to oligo and poly(alkylene terephthalate)sDedicated to Prof. Dr. H. G. Zachmann on the occasion of his 60th birthday (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 741-748 
    Details
    ISSN: 0887-624X
    Keywords: sequence/sequential analysis ; chemical degradation ; ultimate repeating unit ; poly(ethylene terephthalate)/PET ; poly(butylene terephthalate)/PBT ; copolyester ; oligoester ; HPLC ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A specifically tailored reagent was used to label the hydroxyl end groups of poly(ethylene/butylene terephthalate), which is synthesized by transesterification of the corresponding homopolymers. The terminal monomeric unit was then eliminated, together with the attached label, as a low molecular-weight cyclic compound. Specially synthesized reference compounds containing ethylene terephthalate and butylene terephthalate units enabled the terminal monomeric unit to be identified as butylene terephthalate, although the copolymer showed an otherwise random distribution. Despite the practical and theoretical reasons that restrict this sequential degradation to the last monomeric unit for polymers, the principle can be used in a wider range of applications if combined with selective degradation and separation by means of HPLC, which results in chemically uniform oligomers. The ultimate and penultimate monomeric units of ethylene/butylene terephthalate type oligomers can be identified using the cyclodegradation procedure described here. © 1993 John Wiley & Sons, Inc.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1993.080310319
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    An amylopectin tris(phenylcarbamate) chiral stationary phase for high performance liquid chromatography (1993)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 364-367 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; Optical resolution ; Chiral phase ; Amylopectin tris(phenylcarbamate) ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Amylopectin tris(phenylcarbamate) has been evaluated as a chiral stationary phase for HPLC; the influence on its cptical resolving capabilities of mobile phase composition and nature of the alcohol used as modifier has been studied. Separation and resolution of twelve arylalcohol racemates were examined. In most instances, the stationary phase exhibited high optical resolving capacity.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/jhrc.1240160606
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    HPLC coupled with ICPMS for the determination of metalloporphyrins in coal extracts (1993)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 157-160 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; Inductively coupled plasma MS ; Coal extracts ; Gallium porphyrins ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The HPLC-ICPMS determination of gallium porphyrins in various coal extracts is described. The HPLC-ICPMS results are compared with results obtained by HPLC-UV/VIS. The presence of gallium has been confirmed in all the porphyrin macrocycles.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/jhrc.1240160305
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    A new electrophilic polymeric reagent for derivatizing and characterizing aliphatic amines by HPLC with specific dual detection (1993)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 57-59 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; Fluorescence emission detection ; Specific dual detection ; Amperometric oxidation detection ; Polymeric reagent ; Derivatization ; Aliphatic amines ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/jhrc.1240160113
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    Determination of the total phenol content of soils by high speed liquid chromatography with electrochemical detection (1993)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 549-551 
    Details
    ISSN: 0935-6304
    Keywords: Soils ; Total phenols ; HPLC ; Electrochemical detection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The total phenol content of soil samples has been measured using high performance liquid chromatography with electrochemical detection. Soils are extracted with sodium hydroxide solution and the phenols present in the extract are recovered on solid phase C18 cartridges after pH adjustment. The measurement stage employs a short (3 cm) reversed phase column and electrochemical detection. The short column focuses the phenolic species into a single peak which can be integrated. Electrochemical detection provides both sensitivity and selectivity. Hence high speed measurement of a composite peak representing total phenol content is achieved.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/jhrc.1240160909
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    Capillary gas chromatography combined with high performance liquid chromatography for the structural analysis of olive oil triacylglycerols (1993)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 725-730 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; Capillary GC ; Triacyl-sn-glycerol ; Grignard reaction ; Pancreatic lipase ; Fatty acids ; Olive oil ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The triacylglycerol composition of olive oil samples has been determined by stereospecific analysis after partial hydrolysis with ethyl magnesium bromide, derivatization, preparative chiral HPLC, transesterification, and GC quantitation of fatty acid methyl esters. The data obtained for position sn-2 were compared with those from capillary GC analysis of monoacyl sn-2-glycerols after enzymatic lipolysis of triacylglycerols.The determination of triacylglycerols collected by silver ion HPLC and quantified (as fatty acid methyl esters) by GC, together with direct GC analysis on a polar column, have then furnished a comprehensive picture of the triacylglycerol content of olive oil.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/jhrc.1240161211
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    Use of a new HPLC stationary phase for one-step clean-up of human milk for PCDD, PCDF, and PCB analysis (1993)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 129-130 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; Stationary phase ; Internal surface reversed phase (ISRP) ; One-step clean-up ; Human milk ; PCDDs ; PCDFs ; PCBs ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/jhrc.1240160215
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    Amperometric detection after HPLC separation of selected polypeptides and proteins at an electrode modified by mixed valent ruthenium oxide crosslinked with cyanide (1993)
    Weinheim : Wiley-Blackwell
    Electroanalysis 5 (1993), S. 657-661 
    Details
    ISSN: 1040-0397
    Keywords: Modified electrodes ; Reverse-phase ; HPLC ; Proteins ; Peptides ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An indicator electrode, in which a film containing Ru oxides with cyano-crosslinks comprised the active surface, was used in an amperometric detector for ion-exchange and reverse-phase high-performance liquid chromatography (HPLC). The latter used a C-18 column and an eluent of 0.04 M citric acid, 0.1 M KH2PO4, 0.1% trifluoroacetic acid, and 20-80% acetonitrile. Oxytocin, isotocin, vasopressin, tocinoic acid, myoglobin, and ribonuclease A were separated and determined with detection limits at the 1-3 pmol level. The response to ribonuclease A, as a typical example, was linear over the range of 0.050-2.5 μM, with a slope of 15 nA/μM at 0.94 V (vs. Ag/AgCl). A single preparation of the electrode was generally stable for 3 weeks, as long as the analyte concentrations were below 10 μM.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/elan.1140050806
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    Purification and characterization of a cytochrome P-450 from insecticide susceptible and resistant strains of housefly, Musca domestica L., before and after phenobarbital exposure (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 24 (1993), S. 1-19 
    Details
    ISSN: 0739-4462
    Keywords: chromatography ; cytochrome b5 ; monooxygenase ; HPLC ; immunoelectrophoresis ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A cytochrome P-450 (P-450) was purified from abdominal microsomes of untreated and phenobarbital treated susceptible (S+) and insecticide-resistant (LPR) houseflies using HPLC purification procedures. The purified P-450s exhibited the same apparent molecular masses (54,400 dalton) and could not be distinguished from each other on the basis of HPLC chromatographic properties, reduced CO-difference absorbance maxima (447 ± 0.5 nm), or partial NH2-terminal sequences (MLLLLLLIVVTTLYIFAKL). Since these P-450s were indistinguishable and were immunologically identical to cytochrome P-450lpr we conclude that these P-450s are in fact cytochrome P-450lpr. The level of P-450lpr was increased twofold after PB exposure in the S+ strain, while the level of P-450lpr did not change in the LPR strain. Immunoinhibition of ECOD activity with anti-P-450lpr antiserum suggests that PB treatment in S+ house flies induced P-450lpr, and other forms of cytochromes P-450 with high activity toward this substrate. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/arch.940240102
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    Improvement of the enantiorecognition ability of tyrosine-derived chiral stationary phases: Direct resolution of 1,2-amino-alcohols (β-blockers) (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 36-42 
    Details
    ISSN: 0899-0042
    Keywords: tyrosine chiral selector ; enantiomeric separations ; chiral stationary phases ; HPLC ; subFC ; β-blockers ; 1,2-amino-alcohols ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel chiral stationary phase (CSP) derived from tyrosine is evaluated with regard to the first generation commercially available (S)-ChyRoSine-A CSP, under normalphase or reversed-phase liquid chromatographic (NPLC or RPLC) and subcritical fluid chromatographic (SubFC) conditions. The complete scope of application of these CSPs is reviewed. The novel CSP, which bears a bulkier functional group, displays a higher enantiorecognition ability than previously described (S)-ChyRoSine-A toward about 15 families of racemates, whatever the mobile phase conditions.The direct enantiomeric separation of 1,2-amino-alcohols (β-blockers) is carried out on both CSPs. Facile separations are achieved within short analysis times using SubFC mode, whereas very poor separations are obtained using NPLC mode. These results disagree with previous theories (interchangeability between NPLC and SubFC modes).
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    URL: http://dx.doi.org/10.1002/chir.530040109
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    Optical resolution of β-lactams on 1-phenylethylcarbamates of cellulose and amylose (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 122-124 
    Details
    ISSN: 0899-0042
    Keywords: 4-acetoxy-2-azetidinone ; antibiotics ; carbapenem ; HPLC ; chiral stationary phases ; cellulose tris(1-phenylethylcarbamate) ; amylose tris(1-phenylethylcarbamate) ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Optical resolution of six β-lactams was examined by HPLC using chiral stationary phases consisting of tris((R)-, (RS)-, and (S)-1-phenylethylcarbamate)s of cellulose and amylose. All β-lactams were optically resolved at least by one of the carbamates. Amylose tris((S)-1-phenylethylcarbamate) showed high optical resolving abilities for some β-lactams.
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    URL: http://dx.doi.org/10.1002/chir.530040210
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    Chromatographic resolution of the chiral isomers of several β-blockers over cellulose tris(3,5-dimethylphenylcarbamate) chiral stationary phase (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 174-177 
    Details
    ISSN: 0899-0042
    Keywords: chiral resolution ; β-blockers ; HPLC ; cellulose tris(3,5-dimethylphenylcarbamate) chiral stationary phase ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The optical resolution of seven β-blockers which have in common the N-isopropyl-3-aryloxy-2-hydroxypropylamine moiety was carried out by HPLC using the cellulose tris(3,5-dimethylphenylcarbamate) chiral stationary phase to quantitatively characterize the enantioselectivity of these compounds. The capacity factors and separation factors at different column temperature were determined with some qualitative trends derived. A compensation effect was observed for these compounds where there exists an approximately linear relationship between the enantiomeric differences in enthalpic and entropic energies. © 1992 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/chir.530040308
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