Vosmann K, Klein E, Weber N
Institut für Chemie und Physik der Fette, H.P. Kaufmann-Institut, BAGKF, Münster, Germany.
Lipids. 1998 Oct;33(10):1037-41. doi: 10.1007/s11745-998-0303-x.
Base-catalyzed transesterification of acyl lipids with methanol in the presence of trimethylsulfonium hydroxide (TMSH) is an easy and convenient method for the preparation of fatty acid methyl esters for gas chromatography (GC) analyses. Free fatty acids are converted to fatty acid methyl esters by the pyrolytic reaction with TMSH as well. We have found that lipids and other compounds containing thiol groups are also converted easily to the corresponding methyl sulfides (methyl thioethers) by the pyrolytic reaction with TMSH occurring in the injector of the gas chromatograph. For example, alkane thiols such as dodecane thiol and octadecane thiol are converted to the corresponding alkyl methyl sulfides, whereas bis(methylthio) derivatives are formed from alpha,omega-alkane dithiols, e.g., 1,8-octanedithiol, and from 2,3-dimercaptopropan-1-ol (dimercaprol). Furthermore, 3beta-mercaptocholest-5-ene (thiocholesterol) is converted to 3-methylthiocholest-5-ene by the same reaction. The S-methylation reactions which finally lead to the corresponding methylthio derivatives of lipids and other compounds with thiol groups may be of diagnostic value for the structural analysis of such compounds by GC and GC/mass spectrometry.
在氢氧化三甲基锍（TMSH）存在下，酰基脂质与甲醇进行碱催化的酯交换反应，是一种简便易行的制备用于气相色谱（GC）分析的脂肪酸甲酯的方法。游离脂肪酸也可通过与TMSH的热解反应转化为脂肪酸甲酯。我们发现，脂质和其他含硫醇基团的化合物在气相色谱仪的进样器中与TMSH发生热解反应时，也能轻松转化为相应的甲基硫化物（甲硫醚）。例如，十二烷硫醇和十八烷硫醇等烷硫醇会转化为相应的烷基甲基硫化物，而α,ω-烷二硫醇（如1,8-辛二硫醇）和2,3-二巯基丙醇（二巯丙醇）则会形成双（甲硫基）衍生物。此外，3β-巯基胆甾-5-烯（硫代胆固醇）通过相同反应转化为3-甲硫基胆甾-5-烯。最终生成脂质和其他含硫醇基团化合物相应甲硫基衍生物的S-甲基化反应，对于通过GC和GC/质谱对这类化合物进行结构分析可能具有诊断价值。
