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.

Steroid transformation by activated living immobilized Arthrobacter simplex cells

Abstract: A preparation of living Arthrobacter simplex cells immobilized in polyacrylamide gel, which showed steroid-Δ1-dehydrogenase activity, was studied. The entrapped microorganisms catalyzed the transformation of cortisol to prednisolone and this reaction was followed spectrophotometrically or with the aid of thin layer chromatography (TLC) and high pressure liquid chromatography (HPLC). About 40% of the original activity found with free bacteria was retained after immobilization. The steroid dehydrogenase activity of polyacrylamide-entrapped A. simplex could be raised to a minor extent in alcoholic solvents or by addition of a cofactor such as menadione. On incubation in various nutrient media, on the other hand, the activity could be increased considerablyl, usually 7–10 times. Possible causes for the observed increase in activity have been investigated, and microbial growth of the original entrapped microorganisms appears to be the major reason. Frozen activated preparations of immobilized A. simplex showed only a small loss of activity on storage for at least four months. A semicontinuous batch wise operation with immobilized A. simplex in different nutrient media was carried out. At the end of the experiment the steroid transformation capacity was 0.5 g steroid per day per g gel (wet weight).

[1] Thin-layer chromatography of steroids, sterols, and related compounds

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.