Mass spectrometer from Applied Biosystems helps in tyrian purple research

Researchers at Manchester Metropolitan University, UK, are using a mass spectrometer from Applied Biosystems to investigate the composition of tyrian purple.

This is one of the oldest and most prestigious dyes in the ancient world, and is produced exclusively by hypobranchial gland secretions from different molluscan species. Twelve thousand molluscs were needed to produce enough dye to determine 6,6'dibromoindigo as the major structure of the dye, early in the twentieth century.

Tyrian purple and related dyes are still used today, as Malvina Papanastasiou, a postgraduate student in the Department of Chemistry and Materials, explained: "We have studied the composition of tyrian purple dyes produced by marine molluscs originating from Greece, Mexico and Israel; depending on the species, the colour ranges from red to 'iodine-like'. We used mass spectrometry with atmospheric pressure photoionisation, which is more sensitive for the low polarity of the indigoid structures under investigation. One of the most important features of the triple quadrupole instrument is the selected ion monitoring mode used in conjunction with liquid chromatography, which allows the selective and sensitive analysis of the structures present."

"Knowing the exact composition of the dyes will help us in synthesising similar shades in the future, and to analyse relative dyes and artefacts, such as paintings," Malvina concluded.