Extraction of chemical warfare agents from water with hydrophilic–lipophilic balance and C18 cartridges: Comparative study

Efficient extraction of chemical warfare agents (CWAs) from water is essential before subjecting them to gas chromatographic and spectral analysis aiming towards verification of the Chemical Weapons Convention (CWC). It requires development of fast, reliable, simple and reproducible sample preparation of CWAs from water which is likely to be contaminated during deliberate or inadvertent spread of CWAs. This work describes development of a solid-phase extraction method using hydrophilic–lipophilic balance (HLB) cartridges for extraction of CWAs from water. The extraction efficiencies of HLB and C18 cartridges were compared and the results revealed that HLB sorbents performed better. Extracts were analyzed by gas chromatography–mass spectrometry. Extraction parameters, such as extraction solvent, its volume and rinsing solvent were optimized. Best recoveries of target analytes were obtained using 1 mL methanol and limits of detection were achieved up to 0.05 μg/mL with dichloromethane. Precision of the method was found to be less than 9.2% RSD.