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  • Author or Editor: Victor G. Berezkin x
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A new version of TLC with a closed adsorbent layer and an electroosmotic pump has been investigated. The electroosmotic pump was placed on the front of the plate and used to induce rapid movement of the mobile phase. Experimental evaluation of the new version of forced-flow TLC suggests further elaboration of this version of TLC is appropriate.

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Summary

Thin-layer chromatography is one of the most efficient analysis methods that have remained very popular for many decades, despite the high rates of modern science development and the relative simplicity of the method discussed. One should note that the frequency of published works is virtually an estimate of the value of the given method by chemists-analysts. The result of the conducted scientometric study permits to make the conclusion on the fact that the TLC method is most often used in its initial kind as a classical ascending elution of plates with a silica gel layer in a saturated chamber in spite of diversity of chambers, ways of elution, and stationary phases [1]. In the present review article, the main directions of the method development, based on the comparison of published works on TLC during 2 time periods with an interval of 10 years (2008 and 2018), are presented.

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A comparison of the chromatographic behavior of benzoic acids on normal (silica gel), reversed (RP-18), and polyamide-11 plates using thin-layer chromatography (TLC) with controlled gas phase inside the chamber has been performed. This variant of TLC is based on the use of a gas phase moving over the TLC plate for regulation of the stationary and mobile phases as well as the acid—base properties of analytes during the separation process. The feasibility of such an approach is illustrated by the separation of benzoic acid derivatives using carbon dioxide, ammonia, and acetic acid vapor. It was shown that a gradual change of mobile phase acidity makes it possible to enhance separation efficiency and selectivity, this effect being dependent on the type of the stationary phase. The most considerable change in the retention of benzoic acid derivatives was observed for normal-phase plates with silica gel or silica sol, or starch binders used as the stationary phase. An alteration of surface acidity for polyamide and RP-18 plates is not so pronounced as for silica gel ones so that a smaller change in chromatographic parameters of benzoic acid derivatives was observed.

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