Trocylation of 3‐quinuclidinol, a key marker for the chemical warfare agent 3‐quinuclidinyl benzilate, for its enhanced detection at low levels in complex soil matrices by electron ionization gas chromatography–mass spectrometry

• Published in: Rapid communications in mass spectrometry 2021-08, Vol.35 (15), p.e9123-n/a
• Main Authors: Valdez, Carlos A., Leif, Roald N., Vu, Alexander K., Salazar, Edmund P.
• Format: Article
• Language: English
• Subjects: Ambient temperature; Chemical warfare; Chloroformate; Chromatography; Electrons; Gas chromatography; Ionization; Ions; Markers; Mass spectrometry; Sand; Scientific imaging; Sharpness; Soils; Spectroscopy; Substrates
• ISSN: 0951-4198; 1097-0231
• DOI: 10.1002/rcm.9123

Rationale Detection of 3‐quinuclidinol (3Q), a marker for the chemical warfare agent 3‐quinuclidinyl benzilate, is very difficult by gas chromatography–mass spectrometry (GC/MS), providing low, broad signals even when analyzed in isolated form. Therefore, a method that can convert 3Q into a substrate with enhanced detectability by GC/MS would be an important tool for its analysis. Methods 2,2,2‐Trichloroethoxycarbonyl chloride (TrocCl) was used in the derivatization of 3Q in three different soils of varying composition and total organic content (Virginia type A soil, Nebraska EPA standard soil and Ottawa sand) when present at a 10 μg g−1 concentration in each. A direct derivatization protocol and one involving the pre‐extraction of the analyte were evaluated for their individual efficiencies and subsequent analysis using electron ionization GC/MS. Results The practical derivatization of 3Q, when present at low levels (10 μg g−1) in three different soil matrices, was found to be rapid (1 h) and to take place smoothly at ambient temperature (and as low as 4°C). The method detection limit was determined to be 30 ng mL−1 for the Virginia type A soil, 49 ng mL−1 for the Nebraska EPA standard soil and 72 ng mL−1 for the Ottawa sand sample. Conclusions An expedient and practical derivatization method for 3Q, a chemical warfare degradation product difficult to detect by GC/MS, has been realized using trichloroethyl chloroformate. The reaction provides 3Q‐Troc, a derivative with better detectability than 3Q by electron ionization GC/MS such as peak sharpness and a unique mass spectrum for its unambiguous identification.