HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY OF BLUE AND PURPLE INDIGOID NATURAL DYES

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.