Thin-layer chromatography of some organic selenium compounds

The thin-layer chromatographic behavior on silica gel and consequent rapid separation of some selenopyran derivatives together with some intermediates of their synthesis are described. The compounds examined were selenochrom-4-one, selenochroman-4-ol, 2-nitrobenzyl phenyl selenide, 2-aminobenzyl phenyl selenide, and 6H-dibenzo[b,d]selenopyran. The chromatographic results show that it is possible to obtain rapid separations with small amounts (μg) of substance by a simple monodimensional technique using a two-component eluting solvent.     

Thin-layer chromatography of organic sulphates, phosphates and nitrates

Inorganic oxyanions and their corresponding organic esters, such as sulphates, phosphates and nitrates, have been separated by thin-layer chromatography on cellulose and silica gel plates.     

Thin-layer chromatography in spices analysis

Spices are the dried parts of aromatic plants, excepting the leaves, usually used for flavoring, seasoning and imparting aroma in foods. They contain many classes of valuable compounds, which can also exert different biological activities, such as antioxidant and antimicrobial activity. Since spices contain important bioconstituents, they are often adulterated in economical purposes, not only by the botanical and geographical origin, but also by adding or subtracting of different substances which affect in a negative manner their quality. The aim of this paper is to overview the TLC methods used in the analysis of spices, in order to evaluate their composition and biological activities, and also to detect the adulteration.     

Thin-layer chromatography in the analysis of sunscreens

Thin-layer chromatography is a convenient analytical tool for the analysis of sunscreen containing products. This paper covers the details of performing the essential steps in the analysis of both synthetic and natural sunscreens. References to current and past key papers are cited with examples of these sunscreens and updates of advances in tools and techniques to make this an even more important analytical technique.     

Thin-layer chromatography of mycotoxins

TLC has become an extremely powerful, rapid and in most instances inexpensive separation technique in mycotoxicology. This review presents achievements of its applications in this field. General technical aspects of the TLC of mycotoxins that are discussed include extraction and clean-up procedures, adsorbents and solvent systems, detection methods, two-dimensional TLC, high-performance TLC (HPTLC), quantitation and preparative TLC (PLC). Special applications of TLC deal with multi-mycotoxin analyses and with structurally related or individual mycotoxins (aflatoxins, sterigmatocystins, versicolorins, ochratoxins, rubratoxins, patulin, penicillic acid, mycophenolic acid, butenolide, citreoviridin, trichothecenes, cytochalasans, tremorgenic toxins, epipolythiopiperazine-3,6-diones, hydroxyanthraquinones, zearalenone, citrinin, secalonic acids, cyclopiazonic acid, PR toxin, roquefortine, xanthomegnin, viomellein and naphtho-gamma-pyrones).     

Thin-layer chromatography of some organic selenium compounds and their oxygen and sulfur analogs

The Chromatographic behavior of some series of organic selenium compounds and their oxygen and sulfur analogs (urea, thiourea, selenourea; xanthene, thioxanthene, selenoxanthene; xanthone, thioxanthone, selenoxanthone) has been examined by thin-layer chromatography (TLC) on silica gel. The experimental results show the possibility of attaining fast separations on very small amounts of substance (at the microgram level) by simple monodimensional TLC techniques. Urea and its S and Se analogs as well as xanthones are well separated by two- or three-component eluting solvents; xanthenes are not easily screened even by solvent mixtures. The separation of xanthenes from xanthones by the two-dimensional TLC technique is also described. A further result is the possibility of detecting species in trace amounts in the matrix being examined.     

Thin-layer chromatography of inorganic ions

Summary Thin-layer chromatography of iron(II) and (III), cobalt(II), copper(II), and nickel(II) 1-nitroso-2-naphtholates has been described. The separation was effected on a silica gel layer by employing two different solvent systems: benzene-amyl ether (50 25v/v) and benzene-dioxane (40 17v/v). The metal complexes were detected by their characteristic colours.

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Zusammenfassung Die Dünnschichtchromatographie von Eisen(II) und (III), Kobalt(II), Kupfer(II) und Nickel(II) in Form ihrer 1-Nitroso-2-Naphtholate wurde beschrieben. Die Trennung wurde auf einer Kieselgelschichte unter Verwendung zweier Laufmittelsysteme durchgeführt: Benzol-Amyläther (50 25v/v) und Benzol-Dioxan (40 17v/v). Die Metallkomplexe sind an ihrer charakteristischen Farbe kenntlich.

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Résumé On décrit la chromatographie en couche mince des-nitroso-naphtolates de fer-II et -III, cobalt-II, cuivre-Il et nickel-II. On effectue la séparation sur une couche de gel de silice en utilisant deux systèmes différents de solvants: benzène-éther amylique (50 25v/v) et benzène-dioxane (40 17v/v). On décèle les complexes métalliques d'après leurs colorations caractéristiques.