Showing papers on "Thin-layer chromatography published in 1981"
TL;DR: The Salmonella mutation assay has been adapted to a number of experimental procedures used to characterize the chemical components and molecular mechanisms involved in the direct-acting mutagenicity of diesel particle extracts, and the mutagens were found to be unreactive towards purified DNA.
Abstract: The Salmonella mutation assay has been adapted to a number of experimental procedures used to characterize the chemical components and molecular mechanisms involved in the direct-acting mutagenicity of diesel particle extracts. The mutagens were found to be unreactive towards purified DNA. Mutagenic activity was decreased in nitroreductase-deficient bacteria and increased in the absence of oxygen, suggesting that bacterial enzymes active the mutagens. The extract was fractionated by thin layer chromatography using both normal and reverse phase silica gel plates. On normal silica plates, a separation was made between unsubstituted PAH, nitro-PAH and the more polar aromatic compounds. About a third of the mutagenic activity in the particle extract was recovered in fractions containing monosubstituted nitro-PAH compounds. The absorption spectra and reverse phase chromatographic properties indicate 1-nitropyrene is a predominant component but not the only mutagen in these fractions. The remaining activity was in the more polar fractions, and mutagenicity assays using anaerobic conditions and nitro-reductase-deficient bacteria suggest they contain other nitro-substituted compounds.
169 citations
TL;DR: Results indicate that the activated amino acid residue of the polypeptide is COOH-terminal glycine.
123 citations
TL;DR: Analysis of myocardial ethanol intermediary metabolism in isolated, perfused rabbit hearts and whole heart homogenates provides insight into potential biochemical mechanisms contributing to the triacylglyceride accumulation, decreased beta oxidation of fatty acids, and other lipid abnormalities typical of effects of ethanol on the heart.
121 citations
TL;DR: In this article, the fatty acid constituents of the lipid fraction of royal jelly were characterized by thin layer chromatography of corresponding methyl esters, and the most common characteristic of the organic acids was that most contained 8 or 10 carbon atoms, whether saturated or unsaturated, linear or branched.
Abstract: This present work characterizes the fatty acid constituents of the lipid fraction of royal jelly. Among the organic acids found after fractionation by thin layer chromatography of the corresponding methyl esters, the following compounds were identified by combined GC-MS: saturated and unsaturated linear fatty acids, saturated and unsaturated linear and branched dicarboxylic acids, mono-and dihydroxy acids. The most common characteristic of the organic acids was that most contained 8 or 10 carbon atoms, whether saturated or unsaturated, linear or branched.
102 citations
TL;DR: Partition coefficients in n-octanol-water have been determined for the naturally occurring and some synthetic α-amino acids using thin-layer chromatography in different solvent systems as discussed by the authors.
99 citations
TL;DR: A sensitive, reliable, and economical method for the determination of 6 mycotoxins in mixed feeds is described and has been applied to a wide range of mixed feeds, including laboratory animal diets, and raw materials.
Abstract: A sensitive, reliable, and economical method for the determination of 6 mycotoxins in mixed feeds is described. The feed is extracted with chloroform-water and the extract is cleaned up by using a disposable Sep-Pak silica cartridge. The procedure requires less time (15 min from sample extraction to extract preparation) and less solvent (approximately one-tenth) compared with conventional methods and is suitable for a fast, economical screen. Additional cleanup procedures, involving dialysis or extraction into base, are described for samples containing high levels of interfering compounds. Thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) with fluorescence detection are described for identification and estimation of mycotoxins. The method has been applied to a wide range of mixed feeds, including laboratory animal diets, and raw materials. The limit of detection is 1 microgram/kg for all mycotoxins measured by HPLC.
89 citations
TL;DR: The purification of an angiogenic substance from the Walker 256 rat ascites tumor is reported which is mitogenic for fetal bovine aortic endothelial cells in culture and which also stimulates new blood vessel growth in vivo.
68 citations
TL;DR: In this paper, it is shown that metal traces in high-performance liquid chromatographic bonded-phase silica gel interfere with some separations, and a test for such activity, based on the chromatography of beer bitter acids, is described.
62 citations
TL;DR: In this paper, the authors used a pump system in overpressured thin-layer chromatography using a pressurized ultramicro (PUM) chamber to separate substances with optional development distances.
60 citations
TL;DR: The data suggest an enzymatic transfer of methyl groups from S-adenosylmethionine to free fatty acids, and the absence of long lived intermediates.
59 citations
TL;DR: The lymphatic absorption of nonvolatile oxidation products (NVOP) formed during heating of fats was studied and indicated that, within a NVOP class, the various constituents did not present the same absorption rate.
Abstract: The lymphatic absorption of nonvolatile oxidation products (NVOP) formed during heating of fats was studied. Heated colza or soybean oils or synthetic triglycerides containing a definite aromatic or alicyclic fatty acid were fed to thoracic duct-cannulated rats. Tritium-labeled triolein was added to each dietary fat, as an internal standard, in order to calculate the percentage of lymphatic absorption of the ingested NVOP. Results show that 4% of the total polymeric acids, 53% of the total oxidized monomeric acids and 96% of the total cyclic monomeric acids were recovered in the lymphatic lipids. Gas liquid and quantitative thin layer chromatography of these 3 classes indicated that, within a NVOP class, the various constituents did not present the same absorption rate. The lymphatic absorptions of individual oxidized monomers were between 25 and 93%. Concerning the polymer fraction, the lymphatic recoveries were 1% (nonpolar dimers), 6.8% (polar dimers) and 12% (polar oligomers). Aromatic acids were absorbed to a lesser degree (50–60%) than cyclohexenic acids (91–98%).
TL;DR: There is regional metabolism of arachidonate to monohydroxy eicosanoids in the kidney and the renal cortex does not metabolize arachidonic acid through the lipoxygenase pathway.
TL;DR: The response an linearity were studied for about twenty different types of lipids in a quantitative thin-layer chromatographic system equipped with flame ionization detection (TLC-FID), which showed good linearity for most compounds.
TL;DR: Nine solvent systems and three solid supports are evaluated for their efficiency in separating psilocybin, psilocin and other components of crude mushroom extracts by thin-layer chromatography.
TL;DR: The ability of the enzymes used to degrade the appropriate substrate was confirmed by incubating each lipase with a mixture of phosphatidylcholine, phosph atidylethanolamine, phosphAtidylserine, and sphingomyelin for 15 min at 37 OC.
TL;DR: The amount of α-tocopherolquinone in rat liver has been reinvestigated comparing a conventional procedure including saponification and thin layer chromatography followed by high peformance liquid chromatography with the direct HPLC analysis of a total lipid extract.
Abstract: The amount of α-tocopherolquinone in rat liver has been reinvestigated comparing (a) a conventional procedure including saponification and thin layer chromatography followed by high peformance liquid chromatography (HPLC), with (b) the direct HPLC analysis of a total lipid extract. Recovery of added α-tocopherolquinone was quantitative with both procedures. In contrast to a recent report of 124 nmol/g in rat liver, we found no more than 1–4 nmol/g by procedure a and less than 1 nmol/g by procedure b.
TL;DR: An assay is described for the simultaneous determination of dopamine, noradrenaline, adrenaline, dopa, 3,4-dihydroxyphenylacetic acid, 2,3- dihydroxy-phenylglycol, and 3, 4-dhydroxymandelic acid in a small volume of blood plasma of man, rat, dog and rabbit.
Abstract: An assay is described for the simultaneous determination of dopamine, noradrenaline, adrenaline, dopa, 3,4-dihydroxyphenylacetic acid, 3,4-dihydroxyphenyl-ethanol, 3,4-dihydroxymandelic acid and 3,4-dihydroxy-phenylglycol, capable of detecting amounts in the femtomol range The assay is based on the O-methylation of the catechol moiety utilizing S-[3H-methyl]-adenosyl-l-methionine and a partially purified catechol-O-methyl transferase to form the various O-[3H-methyl]-catechol derivatives The O-[3H-methyl]-catechol derivatives are purified by thin layer chromatography, solvent partitions and/or ion exchange chromatography The assay was successfully applied to biological sample It was possible for the first time, to detect free 3,4-dihydroxy-phenylglycol, free 3,4-dihydroxyphenylethanol and 3,4-dihydroxymandelic acid in a small volume (25μl) of blood plasma of man, rat, dog and rabbit The conjoint measurement of catecholamines and their catechol metabolites in minute amounts of biological samples may contribute to a more detailed understanding of catecholamine metabolism in the peripheral and central nervous system
TL;DR: Deoxynivalenol (3,7,15-trihydroxy-12,l3-epoxytrichothec-9-ene-8-one) was extracted from corn with methanol/water (80:20, v/v) and purified by liquid:liquid partitioning and by preparative high pressure liquid chromatography (HPLC) as discussed by the authors.
Abstract: Deoxynivalenol (3,7,15-trihydroxy-12,l3-epoxytrichothec-9-ene-8-one) was extracted from corn with methanol/water (80:20, v/v) and purified by liquid:liquid partitioning and by preparative high pressure liquid chromatography (HPLC). This procedure was used to prepare mg quantities of toxin from field-inoculated corn for reference standards. Analysis of the isolated deoxynivalenol by analytical HPLC, gas liquid chromatography (GLC) and gas liquid chromatography/mass spectroscopy (GLC/MS) indicated the presence of a second compound similar to deoxynivalenol. This compound comigrates with deoxynivalenol on thin layer chromatography plates in chloroform/methanol (90:10, v/v), but can be separated by HPLC on a reverse-phase C8 column with methanol/water (10:90, v/v). GC/MS of the compound and the trimethylsilyl ether derivative gave parent ions of m/e 280 and 424, respectively. These data and NMR data indicate that the compound is 3,15-dihydroxy-12,13-epoxytrichothec-9-ene-8-one, a previously unreported trichothecene.
TL;DR: The authors' data indicate both qualitative and quantitative differences in the chromatogram patterns between the vertebrate classes, but potentially greater qualitative similarity exists between the lower and higher classes than has previously been noted.
Abstract: Brain gangliosides from four vertebrate classes (fish, amphibia, aves, and mammalia) were studied by patterns generated with the use of two-dimensional thin-layer chromatography. In an effort to retain possible alkali-labile gangliosides, samples were not base-hydrolyzed. Resultant chromatograms revealed complex patterns of the major known gangliosides and a number of minor and trace molecular species previously unresolved. More than 30 resorcinol-positive components were detected in mammalian neural samples. Our data indicate both qualitative and quantitative differences in the chromatogram patterns between the vertebrate classes, but potentially greater qualitative similarity exists between the lower and higher classes than has previously been noted.
TL;DR: In this article, the trimsilyl derivatives from polymerised silicate anions in an eight-year-old cement paste have been fractionated by high pressure liquid chromatography (hplc) and the fractions examined by thin layer chromatography, mass spectrometry and infrared spectrometer.
TL;DR: The detection limit of ecdysteroids on reversed-phase plates is 10- -7 g, using fluorescence quenching or vanillin-sulphuric acid spray as mentioned in this paper.
TL;DR: In this article, the authors developed methods for the labeling of acetate and palmitic acid with the positron-emitting radionuclide,11C (T = 20.4 min).
Abstract: Methods have been developed for the labelling of acetate and palmitic acid with the positron-emitting radionuclide,11C (T=20.4 min). Labelling was achieved via carbonation of the appropriate alkyl magnesium bromide (methyl magnesium bromide or n-pentadecyl magnesium bromide) with11C-labelled carbon dioxide produced by the14N(p, α)11C nuclear reaction. The radiochemical yield and speed of each method of labelling are such that a radiochemically pure product is obtained in injectable form and in activity (>10 mCi) suitable for the study of myocardial metabolism by emission-computerised axial tomography. High pressure liquid chromatography and thin layer chromatography were used to assess the radiochemical purity of each radiopharmaceutical. The specific activity of11C-labelled acetate was estimated by an enzymic procedure to be greater than 0.5 Ci/μmole.
TL;DR: In this article, it was shown that although the RF values are directly related to the separations obtained, the RM values are more convenient in the theory of optimization of chromatograpohic systems.
Abstract: It is demonstrated that although the RF values are directly related to the separations obtained, the RM values are more convenient in the theory of optimization of chromatograpohic systems. Graphs for direct plotting of RF values in the RM scale are shown in both logarithmic and linear solvent composition scale. The effects of preadsorption of the solvent vapours and of simultaneous partition betwen the mobile and the stagnant developing solvent on the retention vs. compostion plots are illustrated. Examples are shown for crossing retentions vs. solvent composition plots.
TL;DR: Fishman et al. as mentioned in this paper proposed an open-ended photoacoustic spectroscopy cell for thin-layer chromatography and other applications, which has been used in a variety of applications.
Abstract: Analytical Chemistry is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Open-ended photoacoustic spectroscopy cell for thin-layer chromatography and other applications Victor A. Fishman, and Allen J. Bard Anal. Chem., 1981, 53 (1), 102-105• DOI: 10.1021/ac00224a026 • Publication Date (Web): 01 May 2002 Downloaded from http://pubs.acs.org on February 13, 2009