The use of dopants in high field asymmetric waveform spectrometry.

Ion mobility spectrometry (IMS) is proven core technology for the gas-phase detection of chemical warfare (CW) agents. One disadvantage of IMS technology is that ions of similar mobility cannot readily be resolved, resulting in false alarm responses and a loss of user confidence. High field asymmetric waveform spectrometry (HiFAWS) is an emerging technology for the gas-phase detection of CW agents. Of particular interest is the potential of a HiFAWS-based platform to reduce the number of false alarms by resolving ions that cannot be discriminated using IMS. It has been demonstrated that a water clustering/declustering mechanism can be a dominant process in HiFAWS. Ions that cannot be discriminated in IMS because they possess the same low field mobility value can be resolved using HiFAWS due to differences in the extent of low field ion solvation and high field ion desolvation. When operating in complex environments such as those potentially experienced in military and security arenas, IMS systems commonly employ internal dopants to reduce the number of background responses. It is possible that HiFAWS systems may also require the use of internal dopants for the same reason. It has been demonstrated that dopants employed for use in IMS may not be suitable for use in HiFAWS.

Optimisation of solvent desorption conditions for chemical warfare agent and simulant compounds from Porapak Q using experimental design. Part 2: Extraction of sulphur mustard from steel and glass Porapak tubes.

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.