Simultaneous GC-MS Determination of Azide, Cyanide and Thiocyanate via Phase-Transfer-Catalyzed Pentafluorobenzylation

抄録

A convenient analytical procedure based on one-step, phase-transfer-catalyzed derivatization has been established for the simultaneous determination of azide, cyanide and thiocyanate in aqueous samples by gas chromatography - mass spectrometry (GC-MS). In order to obtain cleaner extracts, a polymer-bound phosphonium salt was employed as the catalyst, and pentafluorobenzyl bromide (PFB-Br) as a derivatization reagent. The extraction and derivatization of these analytes, as well as the concentration of the resultant derivatives into the organic phase were simultaneously achieved during a 30-min phase-transfer-catalyzed process at 38°C. Rapid and reliable GC-MS determination could be readily performed for these analytes, not only in various beverages but also in diluted, large-volume aqueous samples such as food washings. In addition to electron impact ionization MS (EI-MS), negative-ion chemical ionization MS (NICI-MS) was also employed to detect trace-level analytes, as well as to accomplish incontrovertible identification. The detection limits in various beverages were typically 0.1-0.5μg/ml by EI-MS and 25-100ng/ml by NICI-MS, both in the full-scan mode.