Negative ion ESI–MS analysis of natural yellow dye flavonoids : an isotopic labelling study

McNab, Hamish; Ferreira, Ester S B; Hulme, Alison N; Quye, Anita

Negative ion ESI–MS analysis of natural yellow dye flavonoids : an isotopic labelling study

Resource type

Journal article

Creator (person)

McNab, Hamish

Ferreira, Ester S B

Hulme, Alison N

Quye, Anita

Date published

July 7, 2009

Abstract

Flavonoids are amongst the most commonly used natural yellow colourants in paintings, as lakes, and in historical textiles as mordant dyes. In this paper, evidence from isotopically labelled substrates is used to propose negative ion electrospray collision induced decomposition mechanisms of flavones, flavonols and an isoflavone. These mechanisms include a retro-Diels-Alder fragmentation (observed for flavones and flavonols) and an M-122 fragmentation (characteristic of 3â€²,4â€²-dihydroxyflavonols). In addition, the presence of a m/z 125 fragment ion is shown to be characteristic of 2â€²-hydroxyflavonols and an ion at m/z 149 is shown to be characteristic of 4â€²-hydroxyflavones. Applications of these methods are exemplified by the identification of a minor component of Dyer's camomile (Anthemis tinctoria L.) and the identification of the dye source in green threads sampled from an 18th Century Scottish tartan fragment.