Moss C W, Daneshvar M I
Analytical Chemistry Laboratory, Centers for Disease Control, Atlanta, Georgia 30333.
J Clin Microbiol. 1992 Sep;30(9):2511-2. doi: 10.1128/jcm.30.9.2511-2512.1992.
Location of the double-bond position of monounsaturated fatty acids of various bacteria was accomplished with combined gas chromatography-mass spectrometry analysis of dimethyl disulfide (DMDS) derivatives. The monoenoic fatty acids from whole cells were converted to methyl esters and then to DMDS adducts and analyzed by capillary gas chromatography-mass spectrometry. The mass spectra of DMDS adducts gave an easily recognizable molecular ion and two major diagnostic ions attributable to fragmentation between the two CH3S groups located at the original site of unsaturation. Twenty-one relatively novel monoenoic fatty acids were identified among the bacteria studied. All Flavobacterium species contained i17:1 omega 8c, Bacillus alvei contained i16:1 omega 11c and i17:1 omega 12c, and Psychrobacter immobilis contained 12:1 omega 9c. Resolution of cis and trans isomers with capillary gas chromatography and subsequent mass spectrometry permitted positive identification of 16:1 omega 7c and 16:1 omega 7t in Arcobacter (Campylobacter) cryaerophila and 16:1 omega 9c and 16:1 omega 9t in Aerococcus viridans.
通过对二甲基二硫化物（DMDS）衍生物进行气相色谱 - 质谱联用分析，确定了各种细菌中单不饱和脂肪酸双键的位置。将全细胞中的单烯脂肪酸转化为甲酯，再转化为DMDS加合物，然后通过毛细管气相色谱 - 质谱联用进行分析。DMDS加合物的质谱给出了一个易于识别的分子离子和两个主要的诊断离子，这两个离子归因于位于原始不饱和位点的两个CH3S基团之间的裂解。在所研究的细菌中鉴定出21种相对新颖的单烯脂肪酸。所有黄杆菌属物种都含有i17:1 ω8c，蜂房芽孢杆菌含有i16:1 ω11c和i17:1 ω12c，而嗜冷栖冷菌含有12:1 ω9c。通过毛细管气相色谱和随后的质谱联用对顺式和反式异构体进行分离，从而在嗜低温嗜冷弧菌（弯曲菌属）中阳性鉴定出16:1 ω7c和16:1 ω7t，在绿色气球菌中鉴定出16:1 ω9c和16:1 ω9t。
