Chromatographic identification of carbonyl compounds : VI. Thin-layer chromatographic resolution of mixtures of keto acid 2,4-dinitrophenylhydrazones

Abstract

A study has been made of the resolution of a mixture of pyruvic acid, 2-oxobutyric acid, 2-oxoisovaleric acid, 2-oxoisocaproic acid, 2-oxo-3-methylvaleric acid, levulinic acid, 2-oxoglutaric acid and oxalacetic acid 2,4-dinitrophenylhydrazones, and the possible interference of 2,4-dinitrophenylhydrazine in identification of the components, by the application of thin-layer chromatography. With pure keto acid hydrazones (mixture R) as reference standard, the completeness of the isolation by the adsorption and elution technique (part I), of these keto acids as their hydrazones (mixture M) from aqueous ethanol was examined. The partial decomposition of oxalacetric acid hydrazone was also examined by making a comparison of the intensities of the spots of the components of both the test and reference mixtures in the chromatograms.