The quantitative analysis of triglyceride mixtures by thin layer chromatography on silica impregnated with silver nitrate

Abstract

The paper describes a procedure involving thin layer chromatography on silica impregnated with silver nitrate, which makes possible the separation of synthetic and natural glyceride mixtures into classes according to their degree of unsaturation, and within those classes the resolution of certain isomeric unsaturated glycerides. The separations depend upon the ability of compounds having an olefinic double bond to form co‐ordination complexes with the silver ion. For qualitative analysis, developed chromatoplates are sprayed with dibromofluorescein. Reliable quantitative data may be obtained by charring the separated glycerides with phosphoric acid under carefully controlled conditions, and comparing the densities of the charred areas by means of a photodensitometer. Experiments with mixtures of pure synthetic glycerides revealed an error of less than 3%. Glyceride compositions of a number of natural fats have been determined, and compared with compositions obtained by enzymetic hydrolysis of the same samples.