Fast Black K salt: a versatile thin-layer chromatographic visualisation reagent for the differentiation of aliphatic amines

Abstract

The diazonium reagent Fast Black K salt was evaluated for the visualisation of amines and phenols on silica gel thin-layer chromatographic plates. The reagent was shown to differentiate between aliphatic primary and secondary amines by colour. The structures of the coloured reaction products were subsequently determined; aliphatic tertiary amines did not react. Visible spots were obtained with sub-microgram amounts of various chromatographed drug substances, the sensitivity thus being adequate for toxicological drug screening.