Abstract

The application of new sorbent-film coated passive samplers for capture of bulk commercial and military explosives vapours in operationally relevant spaces such as luggage, rooms, vehicles and shipping containers is presented. Samplers were easily integrated with in-service detection technologies with little/no sample preparation required. Ethylene glycol dinitrate (EGDN) was detected within 4 h in a container holding a suitcase packed with 0.2 kg Perunit 28E. Within a 22,000 dm3 room, 1 kg of concealed Seguridad was detected within 24 h and in an adjoining room within 7 days. Exposed samplers also successfully captured components of 1 kg TNT after 72 h and 1 kg concealed Perunit 28E after 6 h in both a furnished room and a large, partially filled shipping container. For the latter, samplers captured detectable residues outside the container after 24 h and were stable during wet weather for 72 h. A one-week trial at three operationally relevant venues including a university, a theatre and a government building revealed a nuisance positive rate of <1.4% (n = 72). Finally, two alternative applications are presented for extraction of liquid samples and use a particulate contact swab showing flexibility for a range of different search activities.

Highlights

  • Analysis was performed using gas chromatography-thermal energy analysis detection (GC-TEA), GC coupled to mass spectrometry (GC-MS) and liquid chromatography-MS (LC-MS)

  • All other compounds could potentially be detected in trials using these commercial and military grade explosives, either as the intact explosives vapours themselves (TNT) or via associated transformation products (e.g. DNTs etc.)

  • The application of a new passive sampler for explosive vapour capture was trialled in a number of different simulated/ operational environments and was readily integrated with existing explosive detection instrumentation

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Summary

Introduction

Results from all three of these large-scale studies showed that selected organic explosives were uncommon in most public places, and in the case of the most recent UK study, only 4 of 501 samples yielding positive results at very low concentrations i.e. 7.5 ng of cyclotrimethylene-trinitramine (RDX), 3.6 ng of nitroglycerin (NG) and 15.2 ng of 2,4-dinitrotoluene (2,4-DNT)[13] Explosives such as TNT, RDX and octahydro-1,3,5,7-tetranitro-1,3,5,7-triazine (HMX) have been previously found in effluents from explosive manufacturing sites as well as surface water and soil samples, due to dissemination into the environment post-military disposal operations[15,16,17]. The use of a variety of commercial and military explosives to test sampler performance provides new knowledge on the kinetics of explosive vapour dissipation in operationally relevant and well-defined spaces as well as robust establishment of best practice guidelines in terms of sampler location, effective distance, exposure times, and the rate of false/negative alarms

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