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Study of the mass spectrometric behaviour of phthalocyanine and azo dyes using electrospray ionisation and matrix‐assisted laser desorption/ionisation
Author(s) -
Conneely A.,
McClean S.,
Smyth W. F.,
McMullan G.
Publication year - 2001
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.483
Subject(s) - chemistry , phthalocyanine , fragmentation (computing) , molecule , desorption , mass spectrometry , electrospray , polyatomic ion , electrospray ionization , ion , photochemistry , inorganic chemistry , organic chemistry , adsorption , chromatography , computer science , operating system
Abstract The negative ion MALDI‐MS and ESI‐MS behaviour of sulphonated copper phthalocyanine dyes has shown the presence of both anionic and radical anionic species. Substituent groups such as sulphonates and linker arms, as are present in commercial dyes such as Remazol TB and Everzol TB, are found to be labile and the dyes undergo in‐source fragmentation in both MALDI‐MS and ESI‐MS. Ions corresponding to sodium salts can be formed. It appears that Cu is firmly bound in the phthalocyanine structure, unlike the corresponding Mg and Al chelates that can undergo demetallation. The application of ESI‐MS n confirmed that these labile groups can be fragmented from the dye molecules and, in addition, SO 2 losses are observed as for EI‐MS. Hydrolysed commercial azo dyes such as Remazol Black B (I) and Remazol Red RB (III) showed both singly and doubly charged molecular anion species as well as sodium salts using negative ion ESI‐MS, but did not desulphonate like the copper phthalocyanine dyes. The application of ESI‐MS n revealed fragmentation of the dye molecules with the loss of entities such as HOCH 2 CH 2 SO 2 C 6 H 4 N 2 (for both dyes) and SO 2 (for Remazol Black B). MALDI‐MS, ESI‐MS and ESI‐MS n can therefore be used for the characterisation of such dyes by exploiting these fragmentation processes, and some structural information can be obtained for the dyes whose structures are not in the public domain. Copyright© 2001 John Wiley & Sons, Ltd.