Assessing a novel contact heater as a new method of recovering explosives traces from porous surfaces

Abstract

Assessing a novel contact heater as a new method of recovering explosives traces from porous surfaces , & NicDaeid, N. (2016). Assessing a novel contact heater as a new method of recovering explosives traces from porous surfaces. Talanta, 148, 721-728. DOI: 10.1016/j.talanta.2015 General rights Copyright and moral rights for the publications made accessible in Discovery Research Portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from Discovery Research Portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain.• You may freely distribute the URL identifying the publication in the public portal. Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. AbstractIt can be very challenging to recover explosive traces from porous surfaces, such as clothing and car seats, compared to non-porous surfaces. The contact heater has been developed as a novel instrument designed to recover explosives traces from porous surfaces. Samples are taken by heating and drawing air across a surface, with the air flowing through a sampling cartridge containing adsorbent polymer beads, which act to trap any recovered explosive material. Any collected explosive can then be eluted from this cartridge using a solvent, prior to analysis. This paper outlines work performed to evaluate the usefulness of the contact heater with regards to the recovery of explosives traces from porous materials. Ethylene glycol dinitrate (EGDN) and triacetone triperoxide (TATP) were chosen as two representative explosives for this study. Quantification was performed using GC-MS for EGDN and LC-MS/MS for TATP. Different sampling temperatures, sampling times and elution solvents were investigated. Recovery was trialled from leather, carpet and denim. Reasonable recoveries of up to 71% were obtained following optimisation. It was also possible to recover TATP from fabrics exposed to TATP vapour in a vapour-laden jar up to two hours after exposure. The contact heater therefore appears to be a very useful tool for the recovery of explosives traces from porous materials.© 2016. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/

The impact of force, time, and rotation on the transfer of ammonium nitrate: A reductionist approach to understanding evidence dynamics

“…10). This was expected, and is in agreement with other studies that have assessed the impact of surface type on the transfer and recovery of forensic materials [30][31][32][33]. It is likely that this is due to the surface topography (as shown in the SEM micrographs of the surfaces (Fig.…”

Toward Locard’s Exchange Principle: Recent Developments in Forensic Trace Evidence Analysis

“…The manner in which explosives samples are collected is a crucial factor in explosives investigations. Yu et al used a contact heater system to recover traces of the high explosives triacetone triperoxide (TATP) and ethylene glycol dinitrate (EGDN) from porous materials . Porous materials are difficult substrates from which to recover explosive traces.…”

“…Yu et al used a contact heater system to recover traces of the high explosives triacetone triperoxide (TATP) and ethylene glycol dinitrate (EGDN) from porous materials. 169 Porous materials are difficult substrates from which to recover explosive traces. The contact heater system was tested on a variety of substrates "spiked" with explosives.…”

Fundamental studies of the adhesion of explosives to textile and non-textile surfaces

“…For example, vacuum sampling can only recover relatively large explosives crystals, solvent extraction may damage the surface of interest, and Raman spectroscopy requires an explosives crystal to be physically located on a surface before it can be analysed, which can be challenging due to the typically small size of explosives crystals. A recent promising candidate for sampling from textile surfaces is the contact heater [15], which heats a surface at the same time as drawing vacuum from it, with volatilised explosives captured within a sampling cartridge. This has proved successful for the recovery of TATP and EGDN from a variety of surfaces, including ceramic tiles, carpet and denim.…”