Abstract
Abstract Thin layer chromatography has been previously applied to the separation and sizing of globular proteins. This paper describes an extension of the method to give rapid determinations of the molecular size distribution of lignosulphonates. These substances are water soluble polydisperse polymers which are well fractionated on columns of the hydrophilic gel substance “Sephadex”. Thin optically uniform layers of Sephadex were prepared on silica plates. Accurate location of samples on the plates yielded chromatograms which were measured spectrophotometrically by transmission at 282 mμ. The chromatograms were reproducible in all respects, to within ± 5%. Although relatively high concentrations of polymer solutions were required for measurement (6–9% of lignosulphonate) it is not thought that chromatograms were in error due to concentration effects. The use of four different Sephadex gels: G-25, G-50, G-75 and G-100, together with a number of narrowly fractionated lignosulphonates of known molecular size, led to a complete molecular size distribution of the polydisperse samples. Up to 32 chromatograms have been obtained in one day. The specialised equipment necessary to this method is not costly, but a good degree of manipulative skill is required.
Published Version
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