Pretreatment Method for Chloramine-T Decon Sample Before GC Analysis of HD and VX

Chloramine-T, especially its solution in weak acidity, is one of the decontaminants for chemical warfare agents (CWAs), HD, and VX. A high CWAs recovery from decontamination (decon) sample via pretreatment was essential for evaluating decontamination effects. This paper performed experiments to optimize pretreatment methods to extract residual CWAs from chloramine-T decon samples before GC analysis. Effects of two neutralization methods, destroying decon activity by 15% Na₂SO₃ or decreasing decon activity by 3% NH₃·H₂O or 4% NaOH, were studied. Results showed they were all suitable for the HD decon sample, but only 4% NaOH was ideal for the VX decon sample. As for extractant, compared with dichloromethane, petroleum ether was more suitable for recovering CWAs from decon samples. A high recovery above 80% could be obtained for HD and VX samples ranging from 10 mg/L to 10,000 mg/L when optimized neutralization and extraction methods were simultaneously carried out.