Chromatographic analysis of blood lipids. Comparison between gas chromatography and thin-layer chromatography with flame ionization detection

Intact human blood plasma lipids of different composition were analyzed by gas chromatography and thin-layer chromatography with flame ionization detection. The reproducibility of the results obtained by gas and thin-layer chromatography was compared. The main advantages and disadvantages of both methods for lipid analysis are discussed. Generally, the variability of the results measured by thin-layer chromatography in series and from day to day was greater than that obtained by gas chromatography.     

Processes dominating forced-flow thin-layer chromatography

Summary The effect of the vapor phase and other special influences on thin-layer chromatography have been investigated. Comparisons were made of the relationships of time vs. developing distance and flow rate vs. efficiency using a planar arrangement of the thin-layer. Covering the layer facilitates the reproducibility and of the migration front but the most effective optimization step for thin-layer chromatography is provided by forced-flow of the mobile phase. It is suggested that planar chromatography with a covered sorbent layer and using a pressurised solvent stream should be calledforced-flow thin-layer chromtatography.     

Planar chromatography at the turn of the century.

An overview of the state-of-the-art of modern thin-layer chromatography (planar chromatography) is presented with emphasis on the complementary features of thin-layer and column liquid chromatographic separations. The reasons for selecting thin-layer chromatography for a particular analysis are identified by its attributes: a disposable stationary phase; simultaneous parallel separations; static detection free of time constraints; storage device for chromatographic information; all sample components are observed in the chromatogram. Future prospects for improved separation performance in TLC using zone refocusing, forced flow and electroosmotic flow methods are discussed as well as increasing zone capacity by using two-dimensional development and coupling to column chromatographic methods. Advances in coupling thin-layer chromatography with spectroscopic methods for structural elucidation are also considered. Finally, some predictions are made for how thin-layer chromatography will be practiced in the future.     

Chromatographic resolution of molecular species of phosphatidylethanolamine as n-acyl-o-methyl derivatives

Phosphatidylethanolamines were converted into the N-acetyl-O-methyl or N-benzoyl-O-methyl derivatives by treatment with acetic anhydride/benzoyl chloride and diazomethane. Methods for the separation of these derivatives by argentation thin-layer chromatography and reversed-phase partition thin-layer chromatography are described. The procedure is especially advantageous for the analysis of phosphatidylethanolamines that are radioactively labelled in the ethanolamine moiety.     

Experience with Quantitative Thin-Layer Chromatography in the Analysis of Drugs in Plasma

Abstract

A survey is presented concerning the possible techniques of quantitative thin-layer chromatography. Most of the possibilities mentioned have been used successfully in our laboratory for the determination of drugs and metabolites in plasma. With respect to our own experience, the advantages and disadvantages of quantitative thin-layer chromatography are discussed.

Although gas chromatography and high-performance liquid chromatography are more popular, quantitative thin-layer chromatography has a high potential in the analysis of drugs in samples of biological origin and should not be neglected in the development of an assay.     

Correlation of TLC,HPTLIC and PMD Results and Their Transfer to HPLC Systems

Abstract

The correlation of the results of five thin-layer chromatographic techniques and their transfer to high performance liquid chromatography are reported. The data obtained indicate that high performance thin-layer chromatographic results are faithfully reproduced by high performance liquid chromatography. Although plates were not activated, and mixed solvents were used, no major differences were observed between thin layer and high performance liquid chromatography.     

Application of over-run thin-layer and gas-liquid chromatography in the separation of closely related C19O2 steroids.

An improved method for the separation of epimeric C19O2 steroids and their related allylic alcohols is described. In this method, the steroids are first separated by over-run thin-layer chromatography, and the unresolved groups are further analysed as free or as trimethylsilyl ether derivatives by gas-liquid chromatography. The behaviour of twenty-one C19O2 steroids was investigated by thin-layer chromatography in four systems and by gas-liquid chromatography in four liquid phases. All steroid pairs of similar polarity were resolved by the combination of these two fractionation procedures.     

Capillary thin-layer chromatography of antibacterial nitrofuran derivatives

Russian Journal of Applied Chemistry - A new version of thin-layer chromatography, capillary thin-layer chromatography, which is similar to traditional planar chromatography in the idea of...     

Thin-layer size-exclusion chromatography of polymers

Modern concepts of thin-layer chromatography of macromolecular compounds are reviewed, including the features and potentialities of thin-layer size-exclusion chromatography.     

Influence of chamber saturation in thin-layer chromatography on theoretical and experimental parameters of mixture separations

The influence of chamber saturation in thin-layer chromatography on theoretical and experimental parameters of mixture separations were examined. Five different types of chambers for development of chromatograms were taken into consideration. The relation found experimentally differed widely from that calculated using O?cik's equation for different method of carrying out of the chromatographic process. The investigations presented here show the possibility of choosing chromatographic chambers which are optimum for theoretical studies on the process of thin-layer chromatography.     

Stability-Indicating Methods for the Determination of Luliconazole by TLC and HPTLC-Densitometry in Bulk Powder and Cream Dosage Form

JPC – Journal of Planar Chromatography – Modern TLC - Rapid and sensitive thin-layer chromatography (TLC) and high-performance thin-layer chromatography (HPTLC)—densitometry...     

Ion Exchange Application of Overpressured Thin-Layer Chromatography

Abstract

The application of overpressured thin-layer chromatography introduced into the field of ion exchange chromatography. The basic differences between overpressured thin-layer chromatography and classical thin-layer chromatography are discussed including the distinction between the separations performed on thin-layer plates containing silica gel and a mixture of ion exchanger material and silica gel. The basic increase of flow velocity of solvent front with the aid of a pressurized ultra-micro chamber and the effect of flow velocity on the height equivalent of the theoretical plates are also presented. For basic amino acids, the flow velocity vs plate height curves show optima at a moderately high rate of development.     

Application of TLC and OPLC in the Determination of Pigments from Natural Products

JPC – Journal of Planar Chromatography – Modern TLC - Planar chromatographic methods thin-layer chromatography (TLC) and over-pressure thin-layer chromatography (OPLC) have been...     

A review of chromatographic methods for determination of synthetic food dyes

The purpose of this work was to present a chromatographic methods to analyse synthetic food dyes. The following techniques has been described: thin-layer liquid chromatography (TLC), high performance thin-layer chromatography (HPTLC), traditional column chromatography, high performance liquid chromatography (HPLC), include: ion-pair chromatography (HPLC IP), reversed phase chromatography (RP HPLC) and high performance ion chromatography.     

The quantitative detection of estrogens and antithyroid drugs by thin-layer and high performance thin-layer chromatography in animal tissue (author's transl)]

Methods of thin-layer chromatography (TLC) and high-performance thin-layer chromatography (HPTLC) were developed for the determination of estrogens and antithyroid drugs in extracts of animal tissues. TLC proved to be suitable for quantities in the range of 200-2000 ng, with a detection limit of 50-200 ng, HPTLC in the range of 10-200 ng, showing calibration curves of good linearity even in extracts. By HPTLC better detection limits, better separation and faster ascending could be achieved than by TLC.     

Planar Chromatography for Quantitative Analysis of Amino Acids in Fermentation Solutions of Industrial Producer Cultures

Proximate procedures for quantitative analysis of amino acids using high-performance thin-layer chromatography were developed.     

The Role of Spacers in Displacement Thin-Layer Chromatography

Abstract

Displacement chromatography generates highly concentrated bands which migrate closely to each other along the stationary phase bed.

Spacer-displacement thin-layer chromatography is a planar method improving the observable resolution by inserting odd compounds (spacers) among the members of displacement train to be separated.

Substances were chromatographed by displacement mode of development using silica plates, chloroform carrier and triethanolamine displacer.

Resolution formula valid for elution chromatography has been adapted to the displacement type of developments. Explanation for the numerical value of required separation is given for various cases of displacement thin-layer chromatography.

Equations are suggested in order to calculate yield, loss and efficiency of displacement chromatography.     

准圆周薄层色谱上行展开的研究

圆周薄层色谱能将样品展开为很细的谱线,具有较高的分辨能力,常用于分析一些难分离的物质。这种色谱方法过去只能采用水平展开方法。我们将普通薄层板修饰成特定形状,用最常见的上行展开法获得近似于圆周薄层的色谱。方法不需要特殊展开装置,应用于皂苷、生物碱的分离鉴定取得很好效果。     

液相色谱法分离金属螯合物的进展

综述了用薄层液相色谱法和柱液相色谱法分离金属螯合物的进展及其在金属离子分析方面的应用。     

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.