Chemical ionization mass spectral analysis of pinacolyl alcohol and development of derivatization method using p-tolyl isocyanate

Abstract

A simple and routine chemical ionization method (CI) providing molecular weight information is developed for the unambiguous identification of 3,3-dimethyl-2-butanol known as pinacolyl alcohol (PA), a potential precursor for prohibited chemical weapons such as Soman, a nerve agent. This method meets the CI criteria used for the evaluation of proficiency tests conducted by OPCW avoiding use of reference chemical. In addition, a derivatization method using p-tolyl isocyanate for the analysis of PA using GC-MS has also been developed for the identification. This derivatization method facilitates the easy analysis of PA at low concentration present in environmental matrices. The efficiency of the derivatization is >99% with 10 fold increase in the sensitivity of the GC-MS signal. The electron ionization mass spectral fragmentation of the p-tolyl isocyanate (PTI) derivatives of three isomeric alcohols is also established. The positive CI of PTI derivatives of these alcohols resulted in molecular ion information and meets the OPCW criteria for CI method of analysis. Further, the retention indices for all the studied alcohols after derivatization help the unambiguous identification of these compounds present in complex environmental matrices.