Topic
Thin-layer chromatography
About: Thin-layer chromatography is a research topic. Over the lifetime, 7494 publications have been published within this topic receiving 124179 citations. The topic is also known as: TLC.
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TL;DR: Simple modifications of technique originally introduced to improve the reproducibility of paper chromatography have now been adapted for thin layers based on peak height measurement with an internal marker correction for quantitative estimation of clinically important monosaccharides in plasma or whole blood.
Abstract: A method is described for the quantitative estimation of clinically important monosaccharides in plasma or whole blood by direct densitometry of chromatographically-separated zones on silica gel layers. Simple modifications of technique originally introduced to improve the reproducibility of paper chromatography have now been adapted for thin layers. The present method is based on peak height measurement with an internal marker correction. Galactose, fructose, D-xylose, and 3-O-methyl glucose can be estimated in addition to glucose, either singly or in combination, within three or four hours, using an initial sample volume of 0.5 ml. With reasonable experience and skill a coefficient of variation of 3 to 6%, depending on sugar concentration, can be achieved without replication, and the limit of sensitivity is about 0.05 mmol/l. When the performance was compared with an automated glucose oxidase/peroxidase system for glucose and the recovery for the other monosaccharides was calculated, the results were satisfactory.
92 citations
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TL;DR: In this paper, a simple and rapid procedure for the simultaneous determination of monoterpenes and diterpenoid resin acids of conifer stem oleoresin is described; it involves tissue extraction with methyl tert-butyl ether and methylation of the resin acids with CH2N2.
Abstract: A simple and rapid procedure for the simultaneous determination of monoterpenes and diterpenoid resin acids of conifer stem oleoresin is described; it involves tissue extraction with methyl tert-butyl ether and methylation of the resin acids with CH2N2. The resin acid methyl esters and the monoterpenes are then analysed in a single gas chromatographic step. Enantiomer composition of the major monoterpene constituents is determined, after preliminary purification by thin layer chromatography, by capillary gas chromatography on a cyclodextrin column. The method is applicable to conifer species of high resin content (Iodgepole pine) and low resin content (grand fir).
92 citations
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TL;DR: The results of chromatography of carbohydrates on thin layers of silica gel in the presence of sodium mono- and dihydrogen phosphate are often better than those of paper chromatography.
92 citations
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92 citations
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TL;DR: Folic acid and 6-formylpterin solutions of pH in the range 4.5–6.0 were photolysed at 350 nm at room temperature and a ‘red intermediate’ is observed, which is thermally oxidised producing 6-carboxypterin on admission of oxygen.
Abstract: Folic acid and 6-formylpterin solutions of pH in the range 4.5–6.0 were photolysed at 350 nm at room temperature. The photochemical reactions were followed by UV–VIS spectrophotometry, thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). In the presence of oxygen, folic acid is photochemically cleavaged yielding 6-formylpterin and p-aminobenzoylglutamic acid. As the photolysis proceeds, 6-carboxypterin arises from 6-formylpterin, as observed when solutions only containing the latter compound are irradiated in the presence of oxygen. In the absence of oxygen, folic acid is not light-sensitive. However, when oxygen free solutions of 6-formylpterin are irradiated, a ‘red intermediate’ is observed, which is thermally oxidised producing 6-carboxypterin on admission of oxygen. The quantum yields of substrates disappearance and of photoproducts formation are reported.
92 citations