Collisional activation mass spectra of M−. ions of azo dyes containing 2‐naphthol

Collisionally activated decomposition mass spectra of M−. ions of azo dyes are presented. The compounds are of general structure Ar(1)NNAr(2), where Ar(1) is substituted phenyl and Ar(2) is 2-naphthol. Characteristic fragment ions observed include m/z 157, which corresponds to the 2-naphthol substituent with cleavage of the NN bond represented as [Ar(2) – N]−.. Ion of general structure [Ar(1)– NH]− are also observed. Parent ion scans of m/z 157 provide a potential screening technique for 2-naphthol-containing axo dyes. Specific results are reported for the chloroform extract of FD&C Red #8, and capillary gas chromatographic introduction is compared with direct exposure probe introduction for the identification of dyes.