Planar chromatography with a forced flow of the mobile phase produced by an electroosmotic pump on a plate with a closed sorption layer

A new variant of thin-layer chromatography (TLC) with a forced flow of the mobile phases produced by an electroosmotic pump on a plate with a closed sorption layer is proposed. The new variant of TLC is tested for separation of dyes with ethanol and acetonitrile as mobile phases. It is established that the new method is 15–33% faster compared to traditional TLC and provides the same or higher efficiency.     

The use of vacuum in thin-layer chromatography with a forced flow of the mobile phase on plates with covered polymer layer

A new version of TLC with a forced flow of the mobile phase has been suggested. The variant involves the use of a TLC plate, the sorption layer on which is covered with a polymer film, and evacuation as an additional driving force for the mobile phase. The advantages of the new method were analyzed; the velocity coefficient of the movement of the mobile phase front was found to be linearly dependent on the rarefaction at the end of the plate.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1143–1146, May, 1996.     

Use of low volatility mobile phases in electroosmotic thin-layer chromatography

A variant of electroosmotic thin-layer chromatography is suggested with the use of low volatility compounds as mobile phases aimed at drastically decreasing the evaporation of the mobile phase and improving the reproducibility of the method. The linear movement velocity of zones of separated compounds is experimentally shown to increase 2-12-fold in electroosmotic chromatography (compared to similar values in traditional TLC). The separation efficiency is also considerably increased.     

Quasi-thin layer chromatography with forced flow of the mobile phase in microchannels packed with a sorbent

A version of the thin-layer chromatography with forced flow of the mobile phase in microchannels packed with a sorbent is proposed. The dependences of retention parametersR _f and the number of theoretical plates in the course of the elution of hydrophilic dyes (naphthol red and methyl red) on the eluent (propan-2-ol) pressure and developing time were studied. The method can be of interest as a simplified version of the forced-flow TLC and would be useful as a micropilot technique for liquid chromatography. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1538–1539, August, 1997.     

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.

     

Simultaneous determination of water-and fat-soluble vitamins by high-performance thin-layer chromatography using an aqueous micellar mobile phase

It is shown that fat-soluble vitamins A and E and water-soluble vitamins B (B₁, B₂, B₆, and B₁₂) can be separated by high-performance thin-layer chromatography using fractional elution. Benzene was used as the first mobile phase, and a 0.02 M aqueous micellar solution of sodium dodecyl sulfate was the second eluant.     

Possibility of calculating the Rm values in thin-layer chromatography using a ternary mobile phase

Summary On the basis of an equation derived it is possible to establish theoretically the R_M values for a ternary mobile phase. The R_M values of phenol and its derivatives, naphthalene and its derivatives and some polycyclic aromatic hydrocarbons were measured. A good agreement has been found between the calculated and the experimentally obtained R_M values. Analysis of the results showed some regularities of certain values obtained in binary systems when related to the ternary mobile phase.     

A variation of circular thin-layer chromatography with closed adsorbent layer

A new variation of circular thin-layer chromatography with an adsorbent layer closed during the experiment and a simple dismountable device for implementation of this technique are suggested.     

Separation of noble metals by circular thin-layer chromatography

Summary A method has been described for the separation and identification of noble metals by circular thin-layer chromatography. The method is simple and convenient and separation is complete within 2 min. Best results have been obtained on alumina layers with acetone/aoetylacetone/2 M hydrochloric acid (100103) as solvent mixture. Reagents used for detection were rubeanic acid, thiourea, and stannous chloride. The following elements could be detected with sensitivities ranging from 0.1 g to 3.0 g: Rh, Ru, Pt, Au, Os, Pd, Ir, and Cu. Interferences are caused by Ni, Go, Mn, and Fe, yet it is possible to distinguish these from the noble metals on separate chromatograms.

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Zusammenfassung Zur Trennung und Identifizierung von Edelmetallen wird das Verfahren der Zirktdar-Dünnschichtchromatographie empfohlen. Die Methode ist einfach durchzuführen und erfordert nur 2 min für eine vollständige Trennung. Am besten hat sich ein Lösungsmittel aus Aceton, Acetylaceton und 2 m Salzsäure (100103) und Aluminiumoxid als Dünnschichtmaterial bewährt. Als Nachweisreagentien werden Rubeanwasserstoff, Thioharnstoff und Zinn(II)-chlorid verwendet. Folgende Elemente wurden mit Empfindlichkeiten zwischen 0,1 und 3,0 g erfaßt: Rh, Ru, Pt, Au, Os, Pd, Ir und Cu. Störungen wurden durch Ni, Co, Mn und Fe verursacht, jedoch können diese von den Edelmetallen auf getrennten Chromatogrammen unterschieden werden.

     

Intermolecular interactions between the mobile phase components and isomeric naphthols in a thin-layer chromatography

The purpose of our work was to investigate intermolecular interactions between the components of a mobile phase (acetone-benzene) and the isomeric naphthols. On the basis of chromatographic, dielectric, and IR measurements it was established that with the mobile phase composed exclusively of benzene the α- and β-naphthol occurred mainly as monomers and were directly adsorbed on silica gel throughout the whole chromatographic process. With the increase of acetone concentration in the applied mobile phases the effectivity of intermolecular interactions between the α- and β-naphthol molecules and those of acetone also increased. The described method can help give approximate evaluations of intermolecular interactions in the chromatographic systems composed of the mobile phase and separated substances.     

Semiquantitative determination of anions by circular thin-layer chromatography

Summary A semiquantitative method for the determination of 11 anions (chromate, chloride, bromide, iodide, bromate, chlorate, ferrocyanide, ferricyanide, thiocyanate, arsenite and sulphite) by making circular spots on chromatoplate with the circular thin layer Chromatographic apparatus and their comparison with sensitivity standards has been developed. The accuracy is ±5% and the procedure is rapid, simple and economical.

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Zusammenfassung Ein semiquantitatives Verfahren zur Bestimmung von elf Anionen (Cr₄ ^2–, Cl^–, Br^–, J^–, BrO₃ ^–, C1O₃ ^–, [Fe(CN)₆]^4–, [Fe(CN)₆]^3–, CNS^–, AsO₃ ^3– und SO₃ ^2–) durch Ringchromatographie auf Dünnschichten und Vergleich mit Standardringen wurde ausgearbeitet. Die Genauigkeit beträgt ± 5%.

     

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.

     

Semiquantitative determination of alkaloids by circular thin-layer chromatography

Summary A semiquantitative method for the determination of 13 alkaloids (nicotine, quinine, strychnine, brucine, ephedrine, pilocarpine, narcotine, cinchonine, ajmaline, atropine, cocaine, papaverine and morphine) from a single drop of solution by making circular spots on chromatoplate with the circular thin-layer Chromatographic apparatus and their comparison with sensitivity standard has been developed. The accuracy is ±5% and the procedure is rapid, simple and economical.

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Zusammenfassung Ein halbquantitatives Verfahren zur Bestimmung von 13 Alkaloiden (Nikotin, Chinin, Strychnin, Brucin, Ephedrin, Pilokarpin, Narkotin, Cinchonin, Aimalin, Atropin, Kokain, Papaverin und Morphin) in 1 Tropfen Lösung durch zirkuläre Dünnschichtchromatographie und Vergleich mit Standard-Ringen wurde ausgearbeitet. Die Genauigkeit des Verfahrens beträgt ±5%.

     

Semiquantitative determination of water-soluble vitamins by circular thin-layer chromatography

Summary A method for semiquantitative determination of water-soluble vitamins such as thiamin hydrochloride, riboflavin, pyridoxine, choline chloride,p-aminobenzoic acid, cyanocobalamine, nicotinic acid and ascorbic acid is described. It involves making circular spots or rings on chromatoplates using circular thin-layer chromatographic apparatus. The method is based on sensitivity and specificity of spot reactions together with comparison of the color intensity of a circular spot with that of sensitivity standard. The accuracy of the method is ± 5%. The usefulness of the procedure has been illustrated by determining the water-soluble vitamins from multi-vitamin tablets and injections.

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Zusammenfassung Eine Methode zur halbquantitativen Bestimmung wasserlöslicher Vitamine wie Thiaminhydrochlorid, Riboflavin, Pyridoxin, Cholinchlorid,p-Aminobenzoesäure, Cyanokobalamin, Nikotinsäure und Ascorbinsäure wurde beschrieben. Sie beruht auf der Herstellung von Kreisflecken oder Ringen im Wege der Dünnschichtchromatographie. Empfindliche und spezifische Reaktionen dienen zum Vergleich der Farbintensität mit Standardlösungen. Die Genauigkeit beträgt etwa ±5%. Das Verfahren wurde an Multivitamintabletten und Injektionslösungen geprüft.

     

Semiquantitative determination of thirty cations by circular thin-layer chromatography

Summary A comprehensive scheme for the semiquantitative determination of 30 metal ions (Ag⁺, Pb²⁺, W⁶⁺, Tl⁺, Fe³⁺, Au³⁺, Mo⁶⁺, Ga³⁺, Sb⁵⁺, Ge⁴⁺, Te⁴⁺, Pt⁴⁺, Pd²⁺, Ru³⁺, Rh³⁺, Cu²⁺, Co²⁺, Ni²⁺, Zn²⁺, Cd²⁺, Cr⁶⁺, Mn²⁺, U⁶⁺, V⁵⁺, Sn⁴⁺, Bi³⁺, Hg²⁺, Ti⁴⁺, Se⁴⁺ and As³⁺) is described. It is based on circular thin-layer chromatographic technique. The error is ± 5% and 16 other metal ions, not included in the analysis scheme because of the non-availability of spray reagents, do not interfere. The determination of each cation has been made with different spray reagents separately and the mean error has been calculated. The analysis of the same cation with different spray reagents provides a useful check on the results. The method holds an excellent promise for the study of airborne particulates and for the determination of trace elements from blood, tissue and bone.

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Zusammenfassung Ein umfassender Analysengang für die halb quantitative Bestimmung von 30 Metallionen wurde beschrieben. Die Ringchromatographie auf Dünnschichten wurde hierzu verwendet. Der Fehler beträgt ±5%. 16 weitere Metallionen, die in Ermangelung geeigneter Sprühreagenzien in den Analysengang nicht aufgenommen wurden, stören nicht. Die Bestimmung jedes einzelnen Kations wurde mit verschiedenen Sprühmitteln vorgenommen; der mittlere Fehler wurde dann berechnet. So ist eine gute Überprüfung der Ergebnisse möglich. Das Verfahren dürfte sich für die Untersuchung der Luftverschmutzung sowie für die Bestimmung von Spurenelementen in Blut, Gewebe und Knochen eignen.

     

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.

     

Semiquantitative determination of noble metals by circular thin-layer chromatography

Summary A semiquantitative method for the determination of rhodium, gold, ruthenium, platinum, osmium, palladium and copper is presented. It involves making circular spots or rings on chromatoplates using the circular thin-layer Chromatographie apparatus. The method is based on sensitivity and specificity of spot reactions and the comparison of the color intensity of a circular spot with that of a standard scale. The accuracy is ± 6% and the procedure is rapid, simple and economical.

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Zusammenfassung Ein halb quantitatives Verfahren zur Bestimmung von Rh, Au, Ru, Pt, Os, Pd und Cu wurde beschrieben. Es beruht auf der Anwendung der Dünnschicht-Kreis-Chromatographie mit Hilfe empfindlicher und spezifischer Tüpfelreaktionen, deren Farbintensität mit Standardreihen verglichen wird. Die Genauigkeit beträgt ± 6%. Das Verfahren ist rasch, einfach und sparsam.

     

Azeotropic mixtures as mobile phase for thin-layer chromatography of organic fluorescent dyes

Reproducible R _f values in the thin-layer chromatography (TLC) of various fluorescent dyes (amino derivatives of naphthoylenebenzimidazole, naphthalimide, benzanthrone, phenalenone, including phosphorus-containing luminophores) were shown to be obtained by elution with binary homogeneous azeotropic mixtures of solvents of different polarity. Some trends in the chromatographic mobility were established governed by the structural features of the groups of compounds under study.