Showing papers on "Thin-layer chromatography published in 1969"
544 citations
TL;DR: A copper acetate spray reagent has been used for the quantitative densitometric thin-layer chromatography of glycolipids and phospholipids from human CNS myelin and the precision ranges between zero and ± 4.5%.
396 citations
TL;DR: Developing poly(ethylene)imine cellulose thin layers with phosphate solutions gives improved resolution of complex mixtures of nucleotides and minimizes the tailing of highly radioactive orthophosphate present in the mixtures and thus facilitates chromatographic analysis of crude acid extracts of phosphate-labeled bacteria.
332 citations
314 citations
TL;DR: A detailed picture of the phospholipid composition of normal human erythrocytes and plasma was obtained by quantitative two-dimensional thin-layer chromatography on silica gel containing an alkaline component.
257 citations
TL;DR: Biological activity of thyrotropin-releasing hormone was abolished by diazotized sulfanilic acid, N-bromosuccinimide, or acid hydrolysis, but was not affected by periodate or by incubation with proteolytic enzymes.
155 citations
TL;DR: A rapid, simple and reproducible method for the quantitative determination of phospholipids after separation by thin layer chromatography has been described and the method was compared with the generally cited methods used for the same purpose.
154 citations
TL;DR: With this procedure it is possible to determine bile salt concentrations ranging from 10–80 mg/100 ml, and can be extended to include individual bile salts if these are first separated by thin-layer chromatography.
116 citations
TL;DR: In this paper, practical considerations concerning the various techniques that may be applicable to the separation of individual steroids by thin-layer chromatography (TLC) have been discussed, including the adsorbent, the preparation of the layer, and the type of solvent system to be employed for development of the chromatoplates.
Abstract: Publisher Summary The simple apparatus and techniques required for the development of thin-layer chromatograms, the high-power of resolution of thin-layer chromatography (TLC), and the possibility of employing a large number of reactions of great specificity and high sensitivity for the visualization of the analyzed compounds are major reasons for the acceptance that TLC has found as a separation procedure. Although TLC is employed in quantification procedures, it is even more widely used for preliminary separations and for purposes of identification. For preliminary separations, TLC is often used in conjunction with other methods of fractionation, such as column-partition chromatography and gas–liquid chromatography. This chapter deals with practical considerations concerning the various techniques that may be applicable to the separation of individual steroids by TLC. Factors that are taken into consideration when TLC is chosen as the method of fractionating mixtures of steroids include the adsorbent, the preparation of the layer, and the type of solvent system to be employed for development of the chromatoplates, and the technique to be used.
73 citations
TL;DR: In this paper, the Pueblito de Allende meteorite was analyzed using thin layer chromatography or combined gas chromatography and mass spectrometry, and the results showed that it was a meteorite of the type of PDE.
Abstract: Organic analysis of Pueblito de Allende meteorite using thin layer chromatography or combined gas chromatography and mass spectrometry
TL;DR: The study shows that bidimensional thin-layer chromatography of carbohydrates with the above impregnants is not feasible, but that excellent monodimensional separations of up to ten sugars can be achieved with the sodium acetate and monosodium phosphate impregnant.
TL;DR: If no NADPH is available for reduction, fatty acid biosynthesis is blocked at the stage of the acetoacetyl-acyl carrier protein intermediate, in this case highly purified fatty acid synthetase from baker's yeast catalyzes, in a derailment reaction, the formation of triacetic acid lactone from acetyl- and malonyl-CoA.
Abstract: If no NADPH is available for reduction, fatty acid biosynthesis is blocked at the stage of the acetoacetyl-acyl carrier protein intermediate. In this case highly purified fatty acid synthetase from baker's yeast catalyzes, in a derailment reaction, the formation of triacetic acid lactone from acetyl- and malonyl-CoA. The identity of the product was shown by the enzymatic incorporation of radioactivity from [1-14C]acetyl-CoA and from recrystallization to constant specific radioactivity. In paper chromatography, thin layer chromatography, and ionophoresis both the chemically synthesized triacetic acid lactone and the enzymatically formed compound migrated with the same RF-values and electrophoretic mobility. By an oxidation with chromic acid according to the procedure of Kuhn-Roth it could be demonstrated that the radioactivity of [1-14C]acetyl-CoA is incorporated only into the C-6 position of triacetic acid lactone. Free triacetic acid and tetraacetic acid lactone do not seem to be formed by fatty acid synthetase. The ratio of the malonyl-CoA utilization for the synthesis of palmitoyl- and stearoyl-CoA to that for the synthesis of triacetic acid lactone was found to be about 90:1. The significance of these findings is discussed. A chemical mechanism for the formation of triacetic acid lactone by fatty acid synthetase is proposed.
TL;DR: Comparison of the extracted lipids with those from similar portions of the same unfixed tissues by thin layer chromatography showed the absence of phosphatidyl ethanolamine in the extract from the fixed tissues, suggesting that the phosphorus had been fixed to the tissue proteins.
TL;DR: A survey on gradient elution TLC is given in this paper, where four processes are known to effect gradients in the mobile phase (elution gradients): frontal analysis of a multicomponent solvent (polyzonal TLC), mechanical alteration of solvent composition in the solvent reservoir (solvent gradient), preimpregnation of the adsorbent by vapors of polar or nonpolar substances (vapor, impregnation gradient), and partial removal of mobile phase during chromatography (flux gradient).
Abstract: A survey on gradient elution TLC is given. At present four processes are known to effect gradients in the mobile phase (“elution gradients”): frontal analysis of a multicomponent solvent (polyzonal TLC), mechanical alteration of solvent composition in the solvent reservoir (solvent gradient), preimpregnation of the adsorbent by vapors of polar or nonpolar substances (vapor, impregnation gradient), and partial removal of mobile phase during chromatography (flux gradient).
TL;DR: Lipids were separated by thin-layer chromatography on a thin silica glass rod coated with adsorbent by developing the chromatogram and the separated compounds were detected by quickly passing the glass rod through the flame of a flame-ionisation detector.
TL;DR: Using plant pigments to demonstrate various chromatographic techniques, including column adsorption, paper adhesion, paper partition, column partition, and thin layer chromatography.
Abstract: Using plant pigments to demonstrate various chromatographic techniques, including column adsorption, paper adsorption, paper partition, column partition, and thin layer chromatography.
TL;DR: This chapter discusses the principal, materials, reagents, and procedures of thin-layer chromatography of citric acid cycle intermediates and some related amino acids, which is adopted successfully in metabolic studies.
Abstract: Publisher Summary This chapter discusses the principal, materials, reagents, and procedures of thin-layer chromatography. The citric acid cycle intermediates and some related amino acids are separated by two-dimensional cellulose thin-layer chromatography. After separation, the compounds are visualized by spraying with an acid-base indicator or ninhydrin. As the compounds studied are normally present in only trace amounts in most biological extracts, it is often necessary to use substrates labeled with isotopes. In these cases, the spots are identified with the help of mixtures of unlabeled known compounds. Techniques for the radioassay of the plates are well developed. This chromatographic technique, including the usage of compounds labeled with 14 C, is adopted successfully in metabolic studies. For detection of the carboxylic acids, the plates are sprayed with bromcresol green indicator. The separation of the eight intermediates of the citric acid cycle is good with the exception of the citratc-isocitrate spots. Biological samples may be deproteinized prior to chromatography by trichloroacetic acid or perchloric acid. The former may be removed by evaporation and the latter removed by adding an equivalent amount of KOH or KHCO 3 .
TL;DR: It was shown that the partially hydrogenated oils all contained fatty acids withtrans double bonds and in the plant oils, thetrans acids were present mainly as elaidic acid, while fatty acids with ω6-structure were not formed during partial hydrogenation of the oils studied.
Abstract: The fatty acid composition of partially hydrogenated arachis (HAO), partially hydrogenated soybean (HSO) and partially hydrogenated herring (HHO) oils and of a normal, refined arachis oil (AO) was studied in detail by means of direct gas liquid chromatography, ultraviolet and infrared spectrophotometry and by thin layer chromatography fractionation on silver nitrate-silica gel plates followed by gas liquid chromatography. It was shown that the partially hydrogenated oils all contained fatty acids withtrans double bonds. In the plant oils, thetrans acids were present mainly as elaidic acid. The HHO showed an almost equal distribution betweentrans 18∶1 ω9,trans 20∶1 ω>9 andtrans 22∶1 ω>9. Sometrans configuration was also found in the C20-and C22-dienes and trienes of the HHO. In all the oils, conjugated fatty acids were present in minor amounts only ( 6, acis, cis and atrans, trans isomer, were present in small amounts. The HHO contained 0.5% 18∶2 ω6 (linoleic acid). Isomers of 18∶2 ω>6 were also found in the HHO. They may be hydrogenation products of higher unsaturated C18-acids orginally present. All the C20- and C22-dienes and trienes were shown to have an ω-chain greater than 6. Fatty acids with ω6-structure were not formed during partial hydrogenation of the oils studied.
LGC1
TL;DR: A screening method for the analysis of organochlorine pesticides in fats and vegetables by semi-quantitative thin-layer chromatography incorporating silver nitrate as a sensitive and selective visualising reagent, and residues estimated by comparison of spot sizes with those of standards.
TL;DR: Thin-layer chromatographic and thin-layer electrophoretic methods are described for the separation of compounds in the vitamin B 6 group and some common metabolites, giving compact spots and permitting reliable determination of these compounds.