Gas-liquid chromatography-mass spectrometry of mono- and dithiols as their tert.-butyldimethylsilyl derivatives.

The use of gas-liquid chromatography and mass spectrometry with derivatizing agents that give stable derivatives and consistent fragmentation patterns allows for accurate identification of a variety of compounds. In this study either N-methyl-N-tert.-butyldimethylsilyltrifluoroacetamide or N-tert.-butyldimethylsilylimidazole were employed to derivatize a range of mono- and dithiols: from ethanethiol to 1-hexadecanethiol and 1,2-ethanedithiol to 1,9-nonanedithiol. When analyzed in this way, the resulting tert.-butyldimethylsilyl derivatives of the 24 thiols tested were readily distinguishable. Complete baseline separation of each derivative by capillary gas-liquid chromatography was achieved, and each produced a prominent mass minus 57 [M+. - 57] fragment ion. The tert.-butyldimethylsilyl-thioethers were colorless and were stable at room temperature for over 3 months. This method may provide a convenient approach to the analysis of thiol compounds from a wide variety of sources.