The parasitic flagellates Trichomonas vaginalis and Tritrichomonas foetus produce indole and dimethyl disulphide: direct characterization by membrane inlet tandem mass spectrometry.

The use of a membrane inlet triple quadrupole mass spectrometer revealed indole as an end product in the growth medium of cultures of the cattle parasite Tritrichomonas foetus and the human parasite Trichomonas vaginalis: formation of indole is enhanced in the presence of added tryptophan. Two different clinical isolates of Trich. vaginalis also produce dimethyl disulphide. Electron impact ionization yielded complex fragmentation mixtures, but the facility for analysis of daughter ions enabled unequivocal assignments. Chemical ionization gave [M + 1]+ species, and tandem mass spectrometry produced identification through daughter ions. The method provides a rapid single-step procedure for the characterization of microbial products without the need for preliminary separation and derivatization.