Abstract
Location of the double-bond position of monounsaturated fatty acids in Campylobacter cryaerophila was accomplished with combined gas chromatography-mass spectrometry analysis of dimethyl disulfide (DMDS) derivatives. The monoenoic fatty acids from whole bacterial cells were converted to methyl esters and then to DMDS adducts gave an easily recognizable molecular ion (M+) and two major diagnostic ions attributable to fragmentation between the two CH3S groups located at the original site of unsaturation. Two previously unidentified acids that distinguish C. cryaerophila from other bacteria were identified as C14:1.omega.7 and C16:1.omega.7 from their mass spectral fragmentation patterns. Resolution of cis and trans isomers by capillary column gas chromatography permitted assignment of the trans isomer to the C16:1.omega.7 acid.