Gas Chromatography/Mass Spectrometry in Analysis of Chemicals Related to the Chemical Weapons Convention

Mass spectrometry in combination with gas chromatography (GC/MS) is at present the most suitable technique for the analysis of chemicals related to the Chemical Weapons Convention (CWC), as GC/MS is capable of providing the required analytical evidence needed to sustain any claim of noncompliance under the Convention. Chemical analysis will be carried out on-site, during an inspection using mobile GC/MS equipment, or off-site, in at least two designated laboratories selected by the Organization for the Prohibition of Chemical Weapons (OPCW). GC/MS analysis under the Convention is focused primarily on qualitative analysis (unambiguous identification) rather than on quantitative analysis. Moreover, GC/MS analysis has to be established under a strict quality assurance/quality control (QA/QC) program. The two most applied techniques in verification analysis are low-resolution electron impact (EI) and chemical ionization (CI) GC/MS under full scan conditions. EI is the oldest and still most used ionization technique for the analysis of CWC related chemicals. Therefore, special attention is paid in this article to the fragmentation under EI conditions of a number of chemicals belonging to the CWC Schedule list. The chemicals placed on this list are the target for the verification analysis, especially the Schedule 1 chemicals, which encompass the well-known chemical warfare (CW) agents such as the nerve agents sarin (GB), soman (GD), tabun (GA) and O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX) and the vesicants mustard gas (HD) and lewisite (L). Sample preparation methods for these chemicals and their degradation products in environmental, synthetic material, and biological sample matrices are described in this article.