Adsorbent In Thin-layer Chromatography Research Articles

Selective separation and determination of isoproterenol on thin layers of bismuth silicate ion-exchanger.

A simple and sensitive method for the separation and determination of isoproterenol from other doping drugs has been developed on thin layers of bismuth silicate, a synthetic inorganic ion exchanger as adsorbent in thin layer chromatography (TLC). A mixture of methanol and 0.1 mol/L formic acid (3:7, v/v) was employed as the mobile phase. The development time was 32 min. The quantitative measurement were performed with a Camag TLC Scanner-3 at wavelength (λ) of 410 nm. The isoproterenol recovery in this procedure was 98.9%. The linear correlation coefficient was greater than 0. 987 1 and the relative standard deviation (RSD) was less than 0.94. The limit of detection (LOD) and limit of quantification ( LOQ) were 7.7 x 10(-7) mol/L and 3.85 x 10(-6) mol/L, respectively. This method has been applied in the determination of isoproterenol in dosage forms and in biological fluids.

Comparative evaluation of selected starches as adsorbent for Thin-layer Chromatography

Purpose: A variety of tested organic and inorganic adsorbents are available today specifically for thin-layer chromatography. The most commonly used is silica gel which is an inorganic adsorbent. Organic substances like cellulose, polyethylene are also used. All these are imported into Nigeria and are unhealthy for economic policies. Most commonly used adsorbent may not be easy to produce locally, but starch, which is a very common product, can be made very readily available. Method: Comparative tests were carried out on cassava, guinea corn and irish potato starches to evaluate and determine suitability as adsorbents for thin-layer chromatography. The starches were used in their natural forms and various modified forms:- formamide, paraffin-impregnated forms and derivatized forms so as to exhibit different properties using different solvent systems to separate different classes of compounds namely alkaloids, amine acids, lipids and steroids with silica gel as standard. Results: The results obtained have proved starch to be a suitable adsorbent both in its naturally occurring and modified forms. Good separations of amino acids and steroids were obtained on natural layers when compared with silica gel, while alkaloids on formamide-impregnated layers and lipids on paraffin-impregnated layers also gave encouraging results. The acetylated starch by suitable modification should produce good results. Conclusion: The suitability of natural starches and its modifications as adsorbents for TLC has thus been established and seems very promising for future use. Keywords: Starch, cassava, guinea corn, Irish potato, adsorbent, thin-layer chromatography. > Tropical Journal of Pharmaceutical Research Vol. 4 (1) 2005: pp. 331-339

Preparation of cellulose stilbene-4-carboxylate and its application to thin-layer chromatography

Photoreactive cellulose stilbene-4-carboxylate (SB-cellulose) with degrees of substitution of up to 1.9 has been prepared by the reaction of regenerated amorphous microcrystalline cellulose with stilbene-4-carbonyl chloride. The stilbene moiety in the SB-cellulose was found to undergo an isomerization from trans to the more polar cis form under irradiation with UV light, resulting in an increase in the swelling ability of the SB-cellulose in water. Application of the SB-cellulose as an adsorbent in thin-layer Chromatography (TLC) was examined. The separation of the spots of appropriate hydrophobic dyes in the TLC was improved using the SB-cellulose as a component of the adsorbent, and more so by irradiation with UV light. Application of this method to the optical resolution of amino acids is suggested as a promising technique for some amino acids such as phenylalanine.

Application of photoresponsive groups‐containing cellulose as an adsorbent for thin layer chromatography

Incorporation de groupes azobenzene. Regulation photochimique de la vitesse d'ecoulement de quelques composes en chromatographie sur couche mince

Influence de l'activité de l'adsorbant en chromatographie d'adsorption sur couches minces

Influence of the activity of the adsorbent in thin-layer chromatography In thin-layer chromatography, the influence of adsorbent activity on chromatographic separations depends upon the nature of the mobile phase, i.e. its affinity for water. This influence may be useful in some chromatographic systems. The activation of layers, however, is not very interesting because of the rapid adsorption of water and the difficulties inherent to working with activated layers.

Relations entre solute, solvant et adsorbant en chromatographie sur couches minces : III. Relation entre la structure moléculaire du solvant et la migration du soluté sur l'adsorbant application à la chromatographie des organophosphorés neutres

Relationships between the solute, solvent and adsorbent in thin-layer chromatography. III. Relationship between the molecular structure of the solvent and the migration of solute on the layer. Application to the chromatography of neutral organophosphorus compounds In view of the fact that solvents can be either hydrogen-bond acceptors or hydrogen-bond donors, some simple chromatographic processes may be schematized. This possibility has been utilized in the chromatography of organophosphorus compounds on silica gel using various solvent systems. The information obtained on solute-solvent, adsorbent-solvent and adsorbent-solute interactions has opened the way for a rapid choice of the most suitable adsorbent and solvent in a given case.

α-Al2O3 as an adsorbent in thin-layer chromatography

The laboratory-made α-Al2O3 was applied in TLC as an adsorbent. The usability of it was determined by the separation of a mixture of test-dyes (butter yellow, Sudan G and indophenol) and calculation of the following coefficients: Rf, Lpt, Ig and t. The comparison was made conducting the same experiments with Al2O3 produced by Woelem. It was stated that the self-made adsorbent permitted satisfactory results to be obtained.

Relations entre soluté, solvant et adsorvant en chromatographie sur couches minces : I. Relations entre la structure moléculaire des composés et leur affinité d'adsorption—application aux composés organophosphorés

Relations between solute, solvent and adsorbent in thin-layer chromatography. I. Relations between the molecular structure of compounds and their adsorption affinity—Application to organophosphorus compounds The R M values of some phosphorus compounds of the (XYZ)PO type, in which X, Y, Z are R, OR or H were determined on silica gel thin layers with a solvent consisting of hexane and acetone. The chromatographic behavior of the compounds in this system is based on the polarity of the phosphoryl group, P(O). We established a linear relationship between the R M values of the compounds and their properties (acid—base, physical, spectral) connected with the polarity of the phosphoryl group. The results show that it is possible to predict and controll the R M values of the compounds in TLC; the establishment of such relationships contributes to the study of the relations between the adsorbent, the solute and the solvent.

Porous glass as an adsorbent in thin-layer chromatography

Porous glass as an adsorbent in thin-layer chromatography

Improved separation of phenols as a result of vapour-induced modification of the adsorbent in thin-layer and column chromatography

Experiments have shown the nature and valuable effect of vapour-induced modification of the activity of the adsorbent in thin-layer chromatography, especially in the case of binary eluents of the nonpolar-polar type, such as carbon tetrachloride/methanol, benzene/ethyl acetate and n-hexane/acetone. These results may contribute to the discussions on the choice of dimensions for elution chambers and their vapour saturation. A distinct relation has also been established between the behaviour of TLC with binary eluents on the one hand and “dry-column” chromatography or normal-column chromatography on the other. Mixtures of phenols containing closely resembling chemical structures have been separated on a preparative scale. Also with two-dimensional thin-layer chromatography the method proved to be very useful.

RF values and structure of the adsorbent in thin layer chromatography using mixed developing solvents

In the chromatographic separation of a mixture of substances a mixed mobile phase is mot frequently used in which, apart from interactions of the adsorbent with the substances separated chromatographically, a significant interaction between the molecules of the same solvent is involved. These interactions may be of various nature, one of which being hydrogen bonding. In this paper only binary solvent systems are considered, in which hydrogen bonds are (a) breaking, (b) forming, (c) breaking and forming, or (d) absent. Quinoline, isoquinoline and 3-methyl-isoquinoline, belonging to class B, according to the classification introduced by EWELL et al. and PIMENTEL AND McCLELLAN, were chosenn in order to demonstrate the effect of the solvent on the substances separated chromatographically with various silica gel adsorbents, of different specific surface area. The results obtained are presented in diagrams in which the ordinates show the R F and R M values and the abscissae the solvent composition. The investigations on the substances of the B group permit us to conclude that the R F values obtained for these substances with binary solvents vary regularly only with some solvents. These variation are especially found with systems in which broken hydrogen bonding is a predominating effect.

RF values and structure of the adsorbent in thin-layer chromatography using pure solvents as the mobile phase

The object of this paper was to investigate experimentally the reproducibility of R F values in thin-layer chromatography, and to establish the effect of the adsorbent, the molecular structure of the solute and the solvent on this reproducibility. In order to solve the problem in question, silica gel adsorbents of various micro-porous structure were used in order to show to what extent the specific surface are of the adsorbents affected the R F values. For this purpose five typical solvents were chosen which belonged to different classes according to the classification introduced by EWELL et al. and PIMENTEL AND McCLELLAN. However, for the purpose of investigating the effect of the kind of molecular structure on the R F value, substances of different molecular size, composed of one, two, or three aromatic rings, were used. The results obtained are presented as “Chromatographic spectra” and their courses are analysed. It has been concluded that the variations in R F values, including Δ R F , depend on the structure of the same type of adsorbent used, but only for some solvents. The specificity of interactions between the solute, solvent and adsorbent is responsible for the changes observed.

Calcium sulfate as an adsorbent for thin-layer chromatography

Calcium sulfate as an adsorbent for thin-layer chromatography

Porous Glass as an Adsorbent for Thin Layer Chromatography.

Porous Glass as an Adsorbent for Thin Layer Chromatography.