A fast‐atom bombardment tandem mass spectrometry screening procedure for the presence of involatile sulphonated dyestuff intermediates

Abstract

AbstractThe introduction of more rigorous regulations aimed at controlling the use of sulphonated dyestuffs and dyestuff intermediates has pointed to the need for screening methods for the presence of these involatile compounds. Although much work has been caried out recently on the mass spectrometric behaviour of these compounds, it has been concerned principally with the production of molecular weight information using novel ionization methods rather than with any attempt to obtain structurally diagnostic fragment ions. In this mass spectrometric investigation of a range of naphthalene sulphonic acid salts, positive‐ion and negative‐ion fast‐atom bombardment (FAB) mass spectra have been obtained and FAB‐tandem mass spectrometry (MS/MS) has been used to acquire spectra (daugher‐ion, parent‐ion and neutral‐loss) in an attempt to develop a useful screening method. On known compounds, best results were found when using a negative‐ion neutral‐loss scan to detect the loss of 64 mass units (corresponding to loss of SO2). This was confirmed by successful use of this scan to screen a sample of sulphonate residues.