Chemical ionization mass spectrometry of dichlofluanid and its major metabolite

Gas chromatographic/mass spectrometric techniques using chemical ionization have been employed to characterize the fungicide dichlofluanid and its major metabolite. The results have indicated some unusual fragmentation pathways for perhalogenmethylmercapto compounds. Use of deuterated ammonia as reagent gas has permitted a comparative assessment of protonation and exchangeable hydrogens within the major fragment ion structures. Resultant structural information has been employed to confirm residue findings in strawberries at the low part‐per‐million level.