Liquid chromatography–mass spectrometry analysis of mauveine and phenosafranins in black precipitate from the Bradford Colour Experience Museum

Abstract

Mauveine chromophores and a family of phenosafranins have been extracted from the Colour Experience Museum black precipitate with boiling ethanol and separated by chromatography. Phenosafranin (287.1295), monomethylphenylsafranin (301.1452) and a dimethylphenosafranin (315.1609) were observed. Tentative evidence for small quantities of N- tert-butylmauveine A and N- tert-butylmauveine B has been found by comparison of the data to standard retention times and accurate mass data. A synthetic method which reproduces the composition of mauveine extracted from the black precipitate, which is rich in mauveine A, is described.