Determination of degradation products of chemical warfare agents in water using hollow fibre-protected liquid-phase microextraction with in-situ derivatisation followed by gas chromatography–mass spectrometry

Hollow fibre-protected liquid-phase microextraction (HF-LPME) together with gas chromatography/mass spectrometry was investigated for the analysis of degradation products of chemical warfare agents in water samples. The degradation products studied were those of nerve and blister agents, and a psychotomimetic agent. Extractions were successfully performed coupled with in-situ derivatisation using a mixture of solvent and derivatising agent. The protection of the moisture-sensitive derivatising agent was afforded by the hollow fibre. Parameters such as extraction solvent, pH, salt concentration, stirring speed and extraction time were optimised using spiked deionised water samples. The linear range established was between 0.005 and 5 μg ml−1 depending on analyte, with squared regression coefficients ranging from 0.9929 to 1.0000. Relative standard deviations ranged from 9% to 22%. As compared to those of solid-phase microextraction, the limits of detection (0.01–0.54 μg l−1) of the newly-developed approach were significantly improved.