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Five historical green dyes from the Historische Farbstoffsammlung, Technical University of Dresden, have been analysed by liquid chromatography – mass spectrometry (LC-MS). The dyes were determined to be formed by the alkylation of either crystal violet or rosaniline and contained both doubly and singly charged ions. One sample had a spread of higher molecular weight doubly charged ions reminiscent of the alkylation of a Hofmann violet. Malachite green was the dye present in one sample. [ABSTRACT FROM AUTHOR]

Liquid chromatography–mass spectrometry has been used to analyse a range of cationic aniline dyes from the 19th century. Mauveine from the Chandler museum is used as a standard for comparison. This consists of a typical W. H. Perkin mixture of mauveine A and B. Mauveine from a historic collection in Dresden is different and consists of mainly mauveine A and a monomethyl mauveine chromophore. Possible synthetic routes and its significance are discussed. Three samples of phenylated rosanilines have been analysed, and a list of 19 possible components compiled. An analysis by liquid chromatography–mass spectrometry works well on this complex mixture giving clear information on retention times and accurate mass molecular weights. Mono-, di- and triphenylrosanilines are present in two samples, and a third sample has mainly monophenylrosaniline. In each sample, a small amount of higher molecular weight homologues appear. The thin-layer chromatography plate, from left to right, has fuchsin or rosaniline then mono-, di- and triphenylrosaniline. The two spots on the right-hand side are blue, and the two spots on the left-hand side are red. [ABSTRACT FROM AUTHOR]