Optimisation of solvent desorption conditions for chemical warfare agent and simulant compounds from Porapak Q™ using experimental design

The vesicant chemical warfare (CW) agent sulphur mustard remains a hazard to personnel involved in demilitarisation activities. Sampling tubes containing Porapak Q™ are used to measure personal exposure to sulphur mustard vapour. Presented here is an evaluation of the solvent desorption parameters employed to remove sulphur mustard from steel and glass tubes containing Porapak Q™. Statistical experimental design was used to elucidate the influence of solvent type, tube type, solvent volume and sonication time on sulphur mustard recovery. The order of increasing recovery was established as iso-octane < hexane = isopropyl alcohol. The same degree of sulphur mustard is recovered on both steel and glass tubes using hexane or isopropyl alcohol, with hexane exhibiting quantitative recovery. The sorbent mass (50 mg) should be increased when using steel tubes as breakthrough has been demonstrated. Given the inert nature of hexane towards sulphur mustard, its favourable chromatographic properties for splitless injection, and its greater recoveries, this solvent should be used for elution of Porapak Q™ tubes for quantitative analysis of sulphur mustard.