Sorbent Film-Coated Passive Samplers for Explosives Vapour Detection Part B: Deployment in Semi-Operational Environments and Alternative Applications

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.

Sampling of explosive residues: The use of a gelatine-based medium for the recovery of ammonium nitrate

“…During this time period there is a decline in the concentration of volatile explosives as well as an increase in the formation of breakdown products [18]. Cotton swabs moistened with an ethanol and water mixture are commonly used for the collection of both inorganic and organic explosive residues [18,20]. Due to the low recoveries obtained from porous surfaces using traditional swabbing methods, vacuum sampling is also employed [21].…”

“…In recent years, the increased use of high-energy improvised explosive materials, such as organic peroxides and homemade mixtures of inorganic and organic explosive compounds, in terrorist attacks has been observed around the world [20,22]. As such, there is a demand for an optimised sampling procedure capable of recovering a wide array of post-blast residues that may be encountered at these scenes.…”

Crime reconstruction and the role of trace materials from crime scene to court

“…A range of studies have addressed the identification of forensically relevant chemical traces in the environment such as illicit drugs in waste water (Castiglioni, Thomas, Kasprzyk‐Hordern, Vandam, & Griffiths, ; Zuccato, Chiabrando, Castiglioni, Bagnati, & Fanelli, ), explosive compounds in waste water (Gamble, Morgan, & Campos, ), and also trace explosive vapors (McEneff et al, ). A key issue for identifying chemical traces in these scenarios is distinguishing the signature of interest from background “noise.” For example, some studies have sought to establish an expected level of background concentration of trace organic explosives in wastewater.…”

Modulated-laser source induction system for remote detection of infrared emissions of high explosives using laser-induced thermal emission

“…Laser-Induced Thermal Emission (LITE) [1][2][3][4][5][6][7] detection of analytes is an important remote detection technique for monitoring hazardous chemicals safely. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] In a homeland security setting, the detection of high explosives (HEs) enabled by LITE spectroscopy could play an important role in maintaining safe operations while conducting real-time detection and fast analysis. [26][27][28][29][30] However, the limits of the detection (LOD) depend on the source to target distance, on the laser power, on the divergence of the source, as well as on the collection efficiency and detector sensitivity.…”