Identification of sugars by circular thin-layer chromatography

Summary A method is described for separation and identification of eight sugars by circular thin layer chromatography. The method is simple and convenient, and separation is complete within 3 minutes. The limit of identification of sugars is very low. The method is specially suitable for routine analysis when quick results are required.

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Zusammenfassung Trennung und Nachweis von acht Zuckern durch Dünnschicht-Ringchromatographie wurden beschrieben. Nach diesem einfachen und praktischen Verfahren ist eine Trennung in 3 Minuten fertig. Die Erfassungsgrenze der Zucker liegt niedrig. Besonders im Routinebetrieb, wenn die Ergebnisse rasch benötigt werden, ist die Methode gut geeignet.

     

Separation and micro determination of lipids by thin-layer chromatography followed by densitometry

Summary A method is presented for the rapid analysis of mixtures of lipids, particularly those from blood serum. The lipids are separated by thin-layer chromatography on silicagel, then charred with 10% aqueous sulphuric acid and the amount of carbon on the slides is measured densitometrically. 5–10 g of lipid mixture are needed for determination of the relative amounts of free sterol, sterol esters, glycerol esters, free fatty acids and total phospholipids.

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Zusammenfassung Es wird eine Methode beschrieben zur schnellen Analyse von Lipidgemischen, insbesonders von Lipiden aus Blutserum. 5–10 g eines Gemisches werden mit Hilfe der Dünnschicht-Chromatographie auf Kieselgel in Sterinester, Glycerinester, freie Steroide, unveresterte Fettsäuren und Phospholipide getrennt. Nach Verkohlung durch Erhitzen mit 10%iger Schwefelsäure werden die verschiedenen Typen densitometrisch bestimmt.

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The investigation forms part of a study on the chemical aspects of atherosclerosis, carried out under the auspices of the Netherlands Organisation of Health Research TNO.     

Identification of seventeen vitamins by circular thin-layer chromatography

Summary A method is described for separation and identification of 17 vitamins by circular-thin layer chromatography. The method is simple and convenient; separation is complete within 2 minutes. The method is very sensitive and is specially suitable for routine identification when quick results are required.

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Zusammenfassung Ein einfaches Verfahren zur Trennung und Identifizierung von 17 Vitaminen durch Dünnschicht-Ring-Chromatographie wird angegeben. Innerhalb von 2 Minuten ist die Trennung vollzogen. Die Methode ist sehr empfindlich und für Routinezwecke besonders geeignet, wenn die Ergebnisse rasch benötigt werden.

     

Identification of twenty amino acids by circular thin-layer chromatography

Summary A method has been developed for the separation and identification of 20 common amino acids by circular thin-layer chromatography. The amino acids are separated to neutral, acid, and basic groups by electrolysis and then identified by circular TLC. The method is simple and development of a chromatoplate is complete in about 3 minutes. The application of the method is illustrated by the analysis of amino acids in foods and in urine.

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Zusammenfassung Zur Trennung und Identifizierung 20 gewöhnlicher Aminosäuren wurde ein chromatographisches Verfahren entwickelt. Die Aminosäuren werden elektrolytisch in neutrale, basische und saure getrennt und dann auf kreisförmiger Dünnschichte chromatographiert. Die Entwicklung des Chromatogramms ist in 3 Minuten beendet. Die Anwendung zur Analyse von Lebensmitteln und Harn wird beschrieben.

     

Identification of alkylpyrocatechols by thin-layer chromatography on silica gel

Conclusions A method was developed for the chromatographic separation of the alkyl derivatives of pyrocatechol employing thin-layer chromatography on plates.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2816–2817, December, 1971.     

Separation of thiazide diuretics and antihypertensive drugs by thin-layer chromatography.

A procedure is reported for the thin-layer chromatographic (TLC) separation and identification of thiazide diuretics and other antihypertensive drugs. Several new solvent systems and a variety of possible detection reagents were examined. Twenty thiazides used routinely in therapy were successfully separated and identified. Use of the TLC systems and combinations of the detecting methods described should be useful for the identification of these drugs in biological fluids and in various dosage forms.     

Determination of semivolatile organic compounds in environmental samples by gas chromatography/mass spectrometry after extraction by cyclic steam distillation

A method was developed for the multiple determination of semivolatile organic compounds found in groundwater, river water, seawater, sediment, and soil. Forty standard compounds were determined: n-alkenes, cycloalkanes, aromatic hydrocarbons, and polycyclic aromatic hydrocarbons. The compounds were isolated from water and soil samples by using an essential oil distillator (cyclic steam distillator) with hexane as a solvent. The extract was cleaned by using a silica gel cartridge with an acetone-hexane solution. The compounds were determined by using a gas chromatograph/mass spectrometer with 12 stable isotope-labeled compounds (surrogate compounds). The efficiencies of recoveries from water samples were 80.0-106% for groundwater, 80.1-106% for river water, and 81.2-103% for seawater. The relative standard deviation (RSD) values were 2.05-16.0% for groundwater, 3.22-16.6% for river water, and 4.45-16.0% for seawater. The efficiencies of recoveries from sediment and soil were 71.5-96.4% and 70.1-99.8%, respectively. RSD values ranged from 2.27 to 16.0% for sediment and from 2.12 to 15.1% for soil. Adjustment of recovery efficiencies of standard compounds by using surrogate compounds gave more accurate values. The present study proved that an essential oil distillator provides satisfactory results for multiple determinations of the semivolatile compounds in environmental waters, sediment, and soil.     

Determination of caprolactam by adsorptive voltammetry after separation by thin-layer chromatography

Caprolactam (2-oxohexamethyleneimine) can be determined in wastewaters and natural waters by adsorptive stripping voltammetry after separation of the product of the reaction between caprolactam and p-(N,N-dimethylamino)benzene-p′-azobenzoyl chloride. When a hanging mercury drop electrode is used with an accumulation time of 60 s in stirred solution, caprolactam can be determined from a lower limit of 0.2 μg ml^?1. With a 360-s accumulation time, linear calibration plots are obtained for 8 × 10^?10?8 × 10^?9 mol l^?1 caprolactam. The effect of interfering sample components is eliminated by the TLC separation.     

Identification of block copolymers and determination of their purity by thin-layer chromatography

The application of adsorption, precipitation and extraction thin-layer chromatography to the identification of block copolymers, determination of their homogeneity (mixtures of homopolymers), and evaluation of their compositional homogeneity by one- and two-dimensional, multistage and gradient methods, is described. To detect the polymers on the thin-layer plate, various methods of detection are used, including those specific for each component of the block copolymer. Examples of analysis of the following block copolymers by thin-layer chromatography are reported: PS-PMMA, PS-PB, PS-PAN, PS-PBG, PI-PMS-PI, PMMA-PBMA, PMMA-PBG, PS-PEO.