New Surface Samplers for Use in Forensic Sampling after a Chemical Incident

After an event involving the deliberate release of toxic chemicals, there is a need to collect samples at the affected site for preservation, recovery, and analysis of the chemical species of interest. These would likely include the active or toxic species as well as chemicals that could serve as chemical attribution signatures that would be important in assigning responsibility for the release. In this preliminary study, a standard gauze pad surface sampling material and technique was compared with the use of silicone rubber samplers placed on glass and coated steel solid surfaces. A range of commercially available silicone rubbers was examined for possible use and one was selected for more extensive evaluation due to its relative ease of handling and minimal interferences with the analytical process. The experiments were conducted with organic chemical species that covered a range of volatilities; two contaminant challenge concentrations were used. The silicone rubber samplers, as applied, were found to consistently collect higher quantities of organic chemicals from the solid surfaces than did the gauze pads. Results of these initial experiments are discussed and ongoing efforts are briefly described.