UCL Centre for the Forensic Sciences


Gwyn Evans

Gwyn Evans

Research synopsis: Detection of vapour phase precursors relevant to home made explosives.

Contact: 35 Tavistock Square, London WC1H 9EZ or email

Detection of vapour phase precursors used in home made explosives.

Background: Detection of vapour phase precursors relevant to home made explosives is an important step in IED threat mitigation, emergency decision making and evidence collection. Rapid and sensitive detection of trace chemicals related to the production of such devices remains challenging, whilst techniques currently employed are costly and often immobile. 

Gas sensor technology: There have previously been efforts to utilise gas sensor technology for the vapour phase detection of explosive precursors. Whilst such sensors are relatively inexpensive and portable, they often lack the selectivity required to distinguish between target gases of similar chemical structure. They also have a high operating temperature (250°C to 400°C), unsuitable for applications in which the presence of a potential ignition source is problematic. 

Aims of research: The aim of this project is to use carbon based nanomaterials, such as carbon nanotubes and graphene, as the active sensing material in an array of gas sensors for explosive precursor detection. It is possible to functionalise carbon materials, increasing their selectivity and sensitivity towards such precursors. Furthermore, room temperature detection is possible, opening up applications and increasing sensor portability. 

Deployment of sensors: One aspect of the project will address options for deployment of sensors and investigate the potential use of unmanned aerial/ground vehicles (UAV's/UGV's) for intelligence gathering on the types of explosive precursors present post incident.

List of publications
Gwyn P. Evans, David J. Buckley, Neal T. Skipper and Ivan P. Parkin, Single-walled carbon nanotube composite inks for printed gas sensors: enhanced detection of NO2, NH3, EtOH and acetone DOI: 10.1039/C4RA09568E (RSC Advances)
Poster presentations
International Crime Science Conference 2014, London, UK: Carbon based nanomaterials for room temperature detection of explosive precursors.
International Nanoscience Student Conference 2013, London Centre for Nanotechnology, UK: Single-walled carbon nanotube modified gas sensors for explosive detection.
Research placements 
University of Delhi 2014- Delhi, India: Project Title - Attachment of metal oxide particles to single-walled carbon nanotubes via chemical functionalisation for selective gas sensors.