High‐performance liquid chromatography of blue and purple indigoid natural dyes

Abstract

Four major components of blue and purple natural dyes of the Indigoid class were separated and spectrally characterised by high‐performance liquid chromatography: indigotin, indirubin, 6‐monobromoindigotin and 6,6′‐dibromoindigotin. It has been shown for the first time that a dyeing with a hypobranchial glandular secretion of Murex trunculus L contains indigotin and both its mono‐and di‐substituted brominated derivative. The analytical features presented may be used to study the composition of old dyes on yarns.