Quantitative thin-layer chromatography with the use of different types of adsorbents

Abstract

In quantitative thin-layer chromatography, the accuracy of measurements is highly dependent on the type of adsorbent and liquid mobile phase used. The present work was undertaken in order to establish the degree to which the type of adsorbent and the specific surface area affect the results of quantitative measurements in thin-layer chromatography. The problem was studied by separating a series of mixtures of substances with different adsorption energies and abilities to form hydrogen bonds, on different adsorbents (including silica gel) with different specific surface areas.The type of mobile phase solvent has an effect on the chromatographic parameters examined. The spots of the separated substances were examined with a densitometer. Planimetric measurements of the spots obtained were also made. It was found that the spot areas as well as the peak areas of the densitometric curves of the developed substances depend on many factors, among which the specific surface area of the adsorbents, the mobile phase, their viscosity coefficient and the migration rate of the phase on the adsorbent layer are of special importance.Generally, the areas of the spots of substances and the peak areas increase in parallel with increases in the specific surface area of the adsorbent. Some deviations from regularity are caused by some factors that are involved in the chromatographic process.