The use of ethanethiol to locate the triple bond in alkynes and the doublebond in substituted alkenes by gas chromatography/mass spectrometry

In order to locate the position of the triple bond in alkynes, several dime thyl disulfide (DMDS) derivatives of alkynes were studied. None of these ad ducts, on EI ionization at 70 eV, allowed the location of the triple bond. However, when DMDS is substituted by ethanethiol, the adducts obtained allo w the determination of the position of the triple bond by GC/MS. A similar study of the DMDS derivatives of highly substituted alkenes was carried out . This work showed that the DMDS derivatives, after ionization at 70 eV, do not reveal the position of the double bond if steric effects are important . In contrast, when ethanethiol was used instead of DMDS, the adducts obtai ned led to the location of the double bond. Copyright (C) 2001 John Wiley & Sons, Ltd.