Showing papers on "Thin-layer chromatography published in 1990"
TL;DR: A digitalis-like factor has been purified to apparent homogeneity from human urine based on the inhibitory effect on [3H] ouabain binding to intact human erythrocytes and showed a prominent digoxin-like immunoreactivity.
124 citations
TL;DR: In this article, the impact on carbohydrate chemistry and biochemistry of the many significant developments in chromatographic analysis during the past decade is discussed and assessed, with a view to a critical evaluation of the contribution of each new method to solving problems in carbohydrate analysis.
120 citations
TL;DR: This relatively simple method is suitable for analyzing the fatty acids in plasma lipids from a 50 microliter finger-tip blood samples from an individual, and it may be useful in wide-scale screening of different individuals to estimate the relative amounts of ingested polyunsaturated fatty acids.
Abstract: A rapid and convenient procedure for the quantitative determination of the fatty acid composition of plasma lipids is described. Human plasma was applied directly to the preadsorbent zones of thin-layer silica gel plates with added antioxidant, internal standards and carriers. The thin-layer chromatography (TLC) plates were partially developed with methanol followed by chloroform/methanol (1∶1, v/v), and then they were fully developed in hexane/diethyl ether/acetic acid (80∶20∶1, v/v/v) to separate the major classes of lipids. Silica gel from regions containing the separated lipids was scraped into screw-capped tubes and treated with boron trifluoride-methanol prior to gas chromatography. The method of direct application to TLC plates gave yields and compositions of fatty acids very similar to the method of applying extracted plasma lipids. This relatively simple method is suitable for analyzing the fatty acids in plasma lipids from a 50 microliter finger-tip blood samples from an individual, and it may be useful in wide-scale screening of different individuals to estimate the relative amounts of ingested polyunsaturated fatty acids.
105 citations
79 citations
TL;DR: Findings are similar to those recently reported for pig epidermis and support the possible role of free sphingosine as a regulator of epidermal differentiation.
68 citations
Book•
27 Apr 1990
TL;DR: This paper clarifies how thin-layer chromatography differs from, but can be used as a pilot procedure for, high-performance liq chromatographic separations of enantiomers.
Abstract: Provides chemists with an in-depth account of chromatographic phenomena and a detailed reference guide to the various choices in optimizing chromatographic separations of enantiomers. Clarifies how thin-layer chromatography differs from, but can be used as a pilot procedure for, high-performance liq
67 citations
TL;DR: A novel delta 12-desaturase from animals, which converts oleic acid to linoleic acid, was characterized in the house cricket, Acheta domesticus, and it is reported that the oleoyl-CoA moiety used as substrate was in the form of a CoA derivative and not in the forms of a phospholipid, as it is for the plantDelta 12- Desaturase.
51 citations
TL;DR: 143 of the organic acids regularly occurring in urine of healthy individuals are identified as methyl esters by gas chromatography-mass spectrometry with respect to their complete chemical structures by pre-fractionating the complex mixture of the total organic acids.
46 citations
Journal Article•
TL;DR: The interaction of acrolein, an alpha,beta-unsaturated aldehyde, with polydeoxyadenylic acid and DNA has been investigated using 32P-postlabeling analysis and two-dimensional nuclear magnetic resonance spectroscopy and mass spectrometry showed the adduct to be 3-(2'-deoxyribosyl-5'-monophosphatyl)-7,8,9-trihydro-9-hydro xy- pyrimido[
Abstract: The interaction of acrolein, an alpha,beta-unsaturated aldehyde, with polydeoxyadenylic acid and DNA has been investigated using 32P-postlabeling analysis. In preliminary experiments, polydeoxyadenylic acid was incubated with excess acrolein and then digested to 3' monophosphates prior to transfer of 32P from [gamma-32P]ATP with T4 polynucleotide kinase. The 3',5'-bisphosphates were 3'-dephosphorylated prior to two-dimensional thin layer chromatography on polyethyleneimine-cellulose layers. Autoradiography provided evidence for the formation of one extra spot of radioactivity, compared to the control. To determine the adduct structure, deoxyadenosine-5'-monophosphate was incubated with a 3-fold excess of acrolein. This material was mixed with a 32P-labeled digest of acrolein-polydeoxyadenylic acid, and the sample was analyzed by ion-pair high performance liquid chromatography. The spot of 32P observed by thin layer chromatography co-eluted with the major product of the acrolein nucleotide reaction mixture, which was purified by ion-pair high performance liquid chromatography. Two-dimensional nuclear magnetic resonance spectroscopy and mass spectrometry showed the adduct to be 3-(2'-deoxyribosyl-5'-monophosphatyl)-7,8,9-trihydro-9-hydro xy- pyrimido[2,3-i]purine(1,N6-propanodeoxyadenosine-5'-monophosphate) . High performance liquid chromatography was used to fractionate digests of acrolein-modified DNA prior to detection of this exocyclic adduct by 32P-postlabeling.
42 citations
TL;DR: Determination de la quantite d'acides gras dans les phospholipides, le diacylglycerol, les acide gras libres, les lipides, et separation par chromatographie sur couche mince.
Abstract: Determination de la quantite d'acides gras dans les phospholipides, le diacylglycerol, les acides gras libres, les lipides. Extraction des lipides des tissus biologiques grâce a un melange de chloforome et methanol et separation par chromatographie sur couche mince. Separation et quantification des acides gras par chromatographie en phase gazeuse-liquide
41 citations
TL;DR: Many steps in the analysis of rough and semirough endotoxins were found to be facilitated by the use of isobutyric acid-ammonium hydroxide solvent.
Abstract: Many steps in the analysis of rough and semirough endotoxins were found to be facilitated by the use of isobutyric acid-ammonium hydroxide solvent. Images
TL;DR: Two-dimensional thin-layer chromatography on cellulose plates has been used for separating and quantifying the three adenosine derivatives: AMP, phosphoribosyl AMP (PRAMP), and (PR)2AMP obtained by venom phosphodiesterase digestion of poly(ADP-ribose).
TL;DR: A thin-layer chromatographic (TLC) method using densitometry is described for the assay and purity control of oxytetracycline and doxycycline and a good correlation was obtained.
TL;DR: Micro-analytical techniques used to study the lipid compositions of samples of skin from seven Dutch bog bodies showed that, while phospholipids have been degraded, other acyl lipids, for example triacylglycerols and steryl esters, may remain intact.
Abstract: A combination of micro-analytical techniques including thin layer chromatography (TLC), gas chromatography (GC). and combined gas chromatography/mass spectrometry (GCIMS) have been employed to study the lipid compositions of samples of skin from seven Dutch bog bodies. TLC showed that, while phospholipids have been degraded, other acyl lipids, for example triacylglycerols and steryl esters, may remain intact. GC and GC/MS analyses, following treatment of the total lipid extracts with acidified methanol, showed the presence of abundant fatty carboxylic acids and sterols. Molecular analysis by GC/MS allowed distinctions to be drawn between components originating from the bog body and the surrounding peat. Additionally, substances derived from microbial alteration of endogenous skin lipids and from the lipids of the micro-organisms themselves can be distinguished.
TL;DR: In order to separate the acylthiourea complexes, high performance thin-layer chromatography methods have been used, whereby both standard methods, adsorption chromatography on silicagel layers and RP-chromatography are applicable.
Abstract: The acyl substituents of N,N-disubstituted N'-acylthioureas have a significant influence on the polarity of the chelates formed. A considerable decrease in the stability of the complexes is observed changing from aromatic to aliphatic acyl substituents. In order to separate the acylthiourea complexes, high performance thin-layer chromatography (HPTLC) methods have been used, whereby both standard methods, adsorption chromatography on silicagel layers and RP-chromatography are applicable. The strong UV-absorption properties of acylthiourea chelates allow a very sensitive detection of the separated complexes. By the method described several metals can be determined simultaneously on a migration distance of 2 to 5 cm.
TL;DR: A chemical method of making milligram amounts of the epoxide intermediates and their diol products adequate for biological tests was developed and the gas-chromatographic retention times and mass spectra of the diol Products were found to match those of biological metabolites.
Abstract: Eicosapentaenoic acid, a major component of fish oil extracts, was recently shown to be metabolized to vicinal diol regioisomers by renal and hepatic cytochrome P-450 epoxygenases. The diol products were also found in the urine of people ingesting fish oil. In the present report, we developed a chemical method of making milligram amounts of the epoxide intermediates and their diol products. Eicosapentaenoic acid was reacted with 0.1 eq.m-chloroperoxybenzoic acid for 15 min. After normal- and reverse-phase high performance liquid chromatography plus capillary gas chromatography and electron impact mass spectrometry, the products were identified as 17,18-cis-epoxyeicosa-5,8,11,14-tetraenoic, 14,15-cis-epoxy-eicosa-5,8,11,17-tetraenoic, 11,12-cis-epoxy-eicosa-5,8,14,17-tetraenoic, 8,9-cis-epoxy-eicosa-5,11,14,17-tetraenoic and 5,6-cis-epoxy-eicosa-8,11,14,17-tetraenoic acids. The total epoxide yield from eicosapentaenoate was 10% per incubation. By reincubating (cycling) the unused substrate 10–20 times, the total epoxide yield could be increased to 66–88%. Epoxide regioisomers were not produced in equal amounts; epoxygenation was facilitated as the distance between the target double bond and carbomethoxy group increased. Upon hydrolyzing the epoxides, the gas-chromatographic retention times and mass spectra of the diol products were found to match those of biological metabolites. In addition, each of these standards was rapidly and quantitatively synthesized in an amount (milligram) adequate for biological tests.
TL;DR: Chromatographic methods are compared with colorimetric, fluorimetric and radioimmunoassay procedures in terms of simplicity of operation, cost and ability to analyse large numbers of specimens.
Abstract: Chromatographic methods (paper chromatography, thin layer chromatography, high performance liquid chromatography, gas chromatography and gas chromatography-mass spectrometry) for the determination of clinically important steroids in biological specimens are reviewed. The emphasis is on the use of gas chromatography, gas chromatography-mass spectrometry and high performance liquid chromatography as reference rather than routine techniques. Chromatographic methods are compared with colorimetric, fluorimetric and radioimmunoassay procedures in terms of simplicity of operation, cost and ability to analyse large numbers of specimens. The importance of correct specimen collection and storage are discussed. Sample preparation techniques for the various analytical methods are described. These include extraction of free and conjugated steroids from serum, plasma, urine and saliva by solvent partition, with polymer-based resins such as Amberlite XAD-2, DEAE-Sephadex and Sephadex resins bonded with various other function groups and, more recently, with chemically bonded reversed-phase silicas.
TL;DR: In this article, a method for the solid phase extraction and thin-layer chromatographic quantitation of sulfamethazine (SMZ) residues in milk is presented, where sulfabromomethazine was added as an internal standard to homogenized milk samples which were then diluted and passed through C 18 solid-phase extraction columns.
TL;DR: A simple chromatographic purification of the naturally occurring ion channel-forming pentadecapeptide gramicidin A is presented, which allows gA to be isolated in gram quantities from the commercially available mixture of isomers after chromatography on silica gel.
TL;DR: Using this procedure, cultured fibroblasts or lymphocytes isolated from whole blood from five patients in whom the urinary organic acid profile was suggestive of deficiency of I are studied, finding that confirmatory enzyme studies should be undertaken, even when the profile of urinary organic acids appears definitive for this deficiency.
Abstract: In this rapid radiochemical assay for 3-hydroxy-3-methylglutaryl-coenzyme A lyase (I) activity in cell extracts, DL-3[glutaryl-3-14C]hydroxy-3-methylglutaryl-coenzyme A is used as substrate and the radiochemical product, [3-14C]acetoacetic acid, is converted to the more stable [3-14C]-3-hydroxybutyric acid in the presence of added NADH and 3-hydroxybutyrate dehydrogenase. Substrate and product are separated and quantified by thin-layer chromatography on cellulose (solvent system: butanol/water/formic acid, 77:13:10 by vol). All reagents for the assay are commercially available. No detailed column chromatography or spectrophotometry is required. Thus the assay is suited for any clinical laboratory. Using this procedure, we studied cultured fibroblasts or lymphocytes isolated from whole blood from five patients in whom the urinary organic acid profile was suggestive of deficiency of I. Three patients had less than or equal to 18% of control I activity in fibroblast or lymphocyte extracts. The other two had activity within the normal range. In one of the latter cases, urinary excretion of three of the characteristic acids disappeared with age, and 3-hydroxyisovaleric acid excretion was within normal limits. The other case presented with urinary excretion of moderate amounts of all four metabolites and the characteristic absence of urinary ketone bodies. Evidently, confirmatory enzyme studies should be undertaken, even when the profile of urinary organic acids appears definitive for this deficiency.
TL;DR: An overview of the combination of chromatographic techniques with mass spectrometry is presented, which includes gas chromatography, thin-layer Chromatography, supercritical fluid chromatography), capillary zone electrophoresis, and especially high-performance liquid chromatography.
Abstract: An overview of the combination of chromatographic techniques with mass spectrometry is presented. It includes gas chromatography, thin-layer chromatography, supercritical fluid chromatography, capillary zone electrophoresis, and especially high-performance liquid chromatography. Present and future developments are discussed.
TL;DR: In this paper, the authors compared a conventional TLC tank with a specially designed continuous linear development chamber for the ether development phase of the quantitation of aflatoxins by bi-directional High Performance Thin Layer Chromatography (HPTLC).
Abstract: A conventional TLC tank was compared with a specially designed continuous linear development chamber for the ether development phase of the quantitation of aflatoxins by bi-directional High Performance Thin Layer Chromatography (HPTLC). No significant difference was detected in the precision of the method. However, the continuous linear development chamber afforded greater accuracy in aflatoxin determination and required only half the development time and a small fraction of the solvent used in the conventional TLC tank. The ability of different concentrations of aqueous acetone, aqueous methanol and aqueous acetone: methanol (1∶1) to extract aflatoxin from naturally contaminated maize was assessed. With each system, the amount of aflatoxin extracted increased as the ratio of organic solvent: water progressed from 50∶50 to 80∶20 and then decreased or remained constant when the composition of the extraction solvent was altered to 90∶10. 80% aqueous acetone was found to extract 27% more aflatoxin than the corresponding aqueous methanol with the mixed solvent system extracting an intermediate amount of toxin. Clean-up of 80% aqueous acetone extracts of maize by elution through phenol (PH) bonded-phase cartridges resulted in poor aflatoxin retention when the proportion of acetone in 5 ml aliquots of extract was greater than 70%. This could be increased to 100% retention by the addition of an equal quantity of methanol prior to dilution with 1% aqueous acetic acid and elution through the cartridge.
TL;DR: The results of the PGE-M assay were compared with those of an assay using the [2H3]methoxime as the internal standard as mentioned in this paper, and the results were quantified by gas chromatography/triple-stage quadrupole mass spectrometry.
01 Jan 1990
TL;DR: In this article, the optimal chloroform-methanol-water mobile phase for the separation of phospholipids by thin-layer chromatography on 5 × 5 cm silica gel was found.
TL;DR: Three spray reagents for the detection of amino-acids on silica-gel thin-layer chromatography plates are reported, which produce various colours, which may be used to identify some of the amino-ACids directly, and assist in their detection.
TL;DR: In this paper, the presence of a range of phenolic compounds including gallic acid, chlorogenic acid, ( + )-catechin, ( − )-epicatechin and ( − ǫ-epigallocatechin and the possible presence of proanthocyanidins and jlavonols.
Abstract: The objective of these experiments was to study the phenolic compounds present in the cormels of the edible aroids, Colocasia spp and Xanthosoma spp. This investigation shows the existence of a range of phenolic compounds which includes gallic acid, chlorogenic acid, ( + )-catechin, ( − )-epicatechin and ( − )-epigallocatechin and the possible presence of proanthocyanidins and jlavonols. Aqueous acetone extracts were examined by thin layer chromatography and high performance liquid chromatography for their phenolic constituents.
TL;DR: In this article, the separation of glycosidically bound volatile components isolated from grapes (Muscat of Alexandria) a and apricot (Rouge du Roussillon) was undertaken using a three-step process.