Gas chromatography–full scan mass spectrometry determination of traces of chemical warfare agents and their impurities in air samples by inlet based thermal desorption of sorbent tubes

Abstract

A sensitive gas chromatography–mass spectrometry (GC–MS) based analytical method was developed for detection of the chemical warfare agents (CWA) and related compounds in air/vapor samples. The method uses a Tenax TA packed GC liner as an air/vapor sampling tube and Programmable Temperature-Vaporization (PTV) GC inlet as the thermal desorber. This approach eliminates secondary focusing step and allows transfer of desorbed analytes as sharp bands directly to the head of GC column. Use of a Peltier element for rapid cooling eliminates need for an external coolant. Minimal logistic and hardware needs make the method relatively inexpensive and especially suitable for a mobile laboratory. The limits of detection (LODs) of 0.8–2.9ng on tube for selected nerve and blister agents were achieved in the full scan MS mode. Simple derivatization method applied for detection of Lewisites 1 and 2 did not affect simultaneous analysis of other agents. The method was extensively evaluated with authentic CWA during the field trainings of the inspectors from the Organization for the Prohibition of Chemical Weapons (OPCW). The environmental area and personal samples were collected for a semi-quantitative determination of averaged airborne CWA concentration levels.