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.     

A Combined Thin-Layer Chromatography/Micro Infrared Method

Abstract

A method is described for the automatic elution of chromatographed compounds on thin-layer chromatography plates and their subsequent identification by micro infrared spectroscopy.

The method is simple, easy to perform in a few minutes, and requires 5 μg of material, 3 mg of KBr powder, and 150 μl of solvent.     

Thin-Layer Chromatographic Separation of the Chloroplast Pigments

Abstract

The separation of the chloroplast pigments is achieved by two-way chromatography on cellulose sheets. The chromatographic system employed is superior to any other thin-layer or paper system yet found.     

Application of Thin-Layer Chromatography to High-Performance Liquid Chromatographic Separation of Steroidal Hormones and Cephalosporin Antibiotics

Abstract

High-performance liquid chromatographic (HPLC) separation of steroidal hormones and cephalosporin antibiotics was investigated by adsorption chromatography and reversed-phase chromatography, respectively.

Prior to the HPLC separation of these pharmaceuticals, silica gel thin-layer adsorption chromatography of steroidal hormones and reversed-phase thin-layer partition chromatography of cephalosporin antibiotics with chemically bonded dimethylsilyl silica gel were performed in order to obtain suitable HPLC separation systems.

In the separation of steroidal hormones, the same binary mobile phase ratios of TLC did not give satisfactory results in HPLC. For the sharp separation in HPLC, solvent strength in the binary solvent mixture used for TLC had to be decreased.

The difference in solvent strength for efficient separation between TLC and HPLC might be attributed to the fact that in HPLC the solvent elution power acts in an isocratic manner while in TLC it acts in a gradient manner.

On the other hand, a correlation of mobility between TLC and HPLC separation for cephalosporin antibiotics was obtained, and the possibility of direct transfer of chromatographic systems from TLC to HPLC for separation of these antibiotics was confirmed.     

The Determination of Ampicillin in Epicillin by the Curvature Inversion Method

Abstract

A method based on the curvature inversion technique has been developed for the determination of ampicillin in epicillin. The results for four epicillin samples are compared with the results obtained by thin-layer chromatography.     

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.     

Argentation Thin-Layer Chromatography of the p-Nitrobenzyl Esters of Gibberellins and Their Precursors

Abstract

Thirteen p-nitrobenzyl esters of gibberellins and their precursors have been separated by thin-layer chromatography on silver nitrate-impregnated silica gel. The fluorescence produced by sulfuric acid was used for their detection.     

Triangular Thin-Layer Chromatography

Abstract

This study illustrates the use of triangular plates in thin-layer chromatographic separations. A comparison between triangular, conventional and circular thin-layer chromatography clearly indicates the superiority of triangular plates in terms of sensitivity, detection limits and savings in plates and solvent.     

Structure and TLC Mobility Relationships for Tebuthiuron and Related Thiadiazoles

Abstract

Tebuthiuron and structurally-related thiadiazoles are separated by thin-layer chromatography on silica gel plates in two developing solvent systems. Relationships between chemical constitution and chromatographic mobility are discussed.     

Circular-Development with Overpressured Thin-Layer Chromatography

Abstract

A novel type modification of circular thin-layer chromatography has been developed, in which the layer is tightly covered by a membrane, eliminating the vapour phase over the sorbent layer. The developing solvent is pumped through the apparatus.     

Separation of Bufotalin and Cinobufotalin by Preparative Liquid Chromatography

Abstract

Complete resolution of bufadienolides by traditional column chromatography, or by thin-layer chromatography (TLC), is quite difficult. Separation of various bufadienolide conjugates by high performance liquid chromatography (HPLC) has been described, but not for resolution of the corresponding genins. A preparative HPLC procedure has been developed for resolving the difficultly separable bufotalin (1) and cinobufotalin (2). A Lobar B column packed with LiChromprep Si-60 was used to separate these bufadienolides employing a recycling procedure.     

Room-Temperature Phosphorescence of Impure Fluorene

Abstract

Impurities in commercial fluorene were detected by thin-layer chromatography and identified by room-temperature phosphorimetry (RTP). Acenaphthene content was analyzed by the standard addition method by using normal RTP measurement procedures with T1(I) as the heavy atom.     

Review of thin-layer chromatography in pesticide analysis: 2014–2016

ABSTRACT

Publications reporting techniques and applications of thin-layer chromatography (planar chromatography) for the separation, detection, qualitative and quantitative determination, and preparative isolation of pesticides and their metabolites are reviewed for the period from November 1, 2014 to November 1, 2016. Analyses are described for a variety of sample types and pesticide classes. In addition to references on residue analysis, studies such as pesticide chromatographic retention, identification and characterization of natural pesticides, metabolism, bioactivity, degradation, soil mobility, and lipophilicity are covered. The unique advantages of thin-layer chromatography in presenting results as a stored image on an open stationary phase are addressed.     

Synthesis and Antimicrobial Activity of Poly (Oxyethylene)S Functionalized with Quaternary Phosphonium End Groups

Abstract

Poly(oxyethylene)s functionalized with quaternary phosphonium end groups were obtained by converting terminal hydroxyl end groups into phosphoniurn ion groups in the polymer-analogous reactions with phosphines and hydrogmu chloride. The products were characterized by: IR, UV. H NMR spectroscopy, thin-layer chromatography.     

High Performance Thin-Film Chromatography in Biological Studies

Abstract

The conventional thin-layer chromatography/TLC/ method of Egon Stahl had not been significantly modified for a long time. But lately much attention was paid to the optimization of the rapidity and sensitivity of the method. The advances in column, gas and liquid chromatography very much contributed to ic. In TLC, like in column chromatography, the use of very fine and homogeneous sorbent fractions was very promising. It appeared especially efficient in liquid chromatography where diffusion coefficients are low.     

Characterization of Liquid-Solid Adsorption Systems by Using TLC Data

Abstract

The thin-layer chromatography (TLC) method is used to measure the excess adsorption isotherms for different binary liquid mixtures on silica gel. These isotherms are interpreted by means of the Langmuir-Freundlich equation, which involves the adsorbent heterogeneity and the difference in the molecular sizes of the components. This equation makes possible the evaluation of the surface phase capacity, equilibrium constant and heterogeneity parameter, which characterize liquid-solid adsorption systems.     

Thin-Layer Chromatographic Separation of 14C-Labeled Metabolites from Photosynthate

Abstract

A method for separating ¹⁴C-labeled metabolites (including key intermediates of the glycolate pathway) from plant extracts by thin-layer chromatography is reported. The method provides for rapid and convenient determination of the ¹⁴C-content of metabolites in leaf samples obtained during kinetic investigations of photosynthesis with ¹⁴CO₂.     

Determination of Tetracycline and Related Compounds by High-Performance Liquid Chromatography

Abstract

An isocratic high-performance liquid chromatography method for the determination of tetracycline and its related compounds is described. The method uses a reverse phase (C₁₈) column, a modified acetonitrile/water mobile phase, and banzoic acid as the internal standard. Elution of all compounds of interest is complete within seven minutes. Results are presented for thirteen commercial capsule formulations and are compared with results by microbiological assay and thin-layer chromatographic methods.