Use of carbonyldiimidazole as a derivatization agent for the detection of pinacolyl alcohol, a forensic marker for Soman, by EI‐GC–MS and LC‐HRMS in official OPCW proficiency test matrices

• Published in: Journal of forensic sciences 2024-07, Vol.69 (4), p.1256-1267
• Main Authors: Valdez, Carlos A., Kaseman, Derrick C., Dreyer, Mark L., Hok, Saphon, Vu, Alexander K.
• Format: Article
• Language: English
• Subjects: 1,1‐carbonyldiimidazole; Alcohol; Carbonyls; Chemical weapons; Chromatography; EI‐GC–MS; Gas chromatography; Imidazole; LC‐HRMS; Liquid chromatography; Low molecular weights; Mass spectrometry; Nerves; OPCW; pinacolyl alcohol; Prohibition; Scientific imaging; Soman
• ISSN: 0022-1198; 1556-4029; 1556-4029
• DOI: 10.1111/1556-4029.15527

Pinacolyl alcohol (PA), a key forensic marker for the nerve agent Soman (GD), is a particularly difficult analyte to detect by various analytical methods. In this work, we have explored the reaction between PA and 1,1′‐carbonyldiimidazole (CDI) to yield pinacolyl 1H‐imidazole‐1‐carboxylate (PIC), a product that can be conveniently detected by gas chromatography–mass spectrometry (GC–MS) and liquid chromatography‐high‐resolution mass spectrometry (LC‐HRMS). Regarding its GC–MS profile, this new carbamate derivative of PA possesses favorable chromatographic features such as a sharp peak and a longer retention time (RT = 16.62 min) relative to PA (broad peak and short retention time, RT = 4.1 min). The derivative can also be detected by LC‐HRMS, providing an avenue for the analysis of this chemical using this technique where PA is virtually undetectable unless present in large concentrations. From a forensic science standpoint, detection of this low molecular weight alcohol signals the past or latent presence of the nerve agent Soman (GD) in a given matrix (i.e., environmental or biological). The efficiency of the protocol was tested separately in the analysis and detection of PA by EI‐GC–MS and LC‐HRMS when present at a 10 μg/mL in a soil matrix featured in the 44th PT and in a glycerol‐rich liquid matrix featured in the 48th Official Organization for the Prohibition of Chemical Weapons (OPCW) Proficiency Test when present at a 5 μg/mL concentration. In both scenarios, PA was successfully transformed into PIC, establishing the protocol as an additional tool for the analysis of this unnatural and unique nerve agent marker by GC–MS and LC‐HRMS.