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

Abstract

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.

Microsynthesis and mass spectral study of Chemical Weapons Convention related 2‐alkyl‐1,3,6,2‐dioxathiaphosphocane‐2‐oxides

“…While the mass spectra of these chemicals are very different from those of other acyclic phosphonates2, 9 and other reported cyclic phosphonates,15 the mechanisms of their mass spectrometric fragmentation are consistent with other classes of phosphonates. In this paper the mass spectra in both electron ionization and chemical ionization via gas chromatography/mass spectrometry (GC/MS), and electrospray (ESI) mass spectra for liquid chromatography/mass spectrometry (LC/MS) are given and the possible fragmentation pathways of the chemicals are discussed.…”

“…For acyclic dialkyl alkylphosphonate esters, fragmentation of the EI molecular ion proceeds via loss of the alkyl groups due to breaking of the O‐alkyl bond and transfer of H atoms to the oxygen 2. The alkyl groups are lost as allylic radicals.…”

“…The base peak in these acyclic esters is generally the protonated alkylphosphonic acid – resulting from the loss of all O‐alkyl groups. The presumed structure is given below: where R = methyl, ethyl and propyl results in m/z 97, 111 and 125, respectively, the typical base peaks in these spectra 2. Typically, both the molecular ion and the loss of the alkyl groups are minor ions indicating the high relative stability of the protonated phosphonic acid in acyclic dialkyl alkylphosphonates.…”

“…In the case of the broad chemical classes, the number of chemicals covered is so large that having analytical data on all of them is impossible. However, the mass spectra of these chemicals tend to be very similar and are often characteristic of a class of chemicals,2 such as phosphonofluoridates (1.A.01),3, 4 phosphoramidocyanidates (1.A.02),5 phosphonothiolates (1.A.03),6, 7 phosphonodifluoridates (1.B.09),8 acyclic phosphonates (2.B.04),2, 9 phosphoramidates (2.B.06),10 phosphonic acids (2.B.04),11, 12 etc. This means that it can be difficult to distinguish one member of a class from another simply by its mass spectrum, but having a number of spectra for a given class of compounds may be sufficient for determining if any member of the class is present.…”

Reaction of Lewisite-1 with Alcohols, Diols, and Thiols in Water—A Simple Method of Derivatization of Thiodiglycol

“…Thus, 1,2-ethanedithiol 5, 5−10 1,3-propanedithiol 6 5,6,10,11 and their homologues up to 1,8-octanedithiol 6 in water, ethanol, 2-propanol or acetone, as well as 3,4-dimercaptotoluene (DMT 7) 10,12 in hexane transform L1 into appropriate 5-to 11-membered cyclic thioesters, which are stable derivatives and easy to identify on GC/MS. Also 1,2-propanedithiol (British anti-Lewisite, BAL 8) reacts with Lewisite-1 in water to form a stable and non-toxic 5-membered arsonodithiolite, preventing the toxic Lewisite effects.…”