An assessment of four solvents for the recovery of 2-chlorobenzylidenemalononitrile and capsaicins from "CS" and "Pepper" type lachrymator sprays, and an examination of their persistence on cotton fabric.
The rising incidence of assaults involving lachrymator sprays has led to an increase in items being submitted to this laboratory for the analysis of the associated chemical residues. The following work was undertaken to identify an efficient solvent with which to extract the compounds of interest from cotton fabric. The persistence and subsequent recovery of such compounds was also examined following protracted exposure to wind and rain. Ethyl acetate was established as the most efficient solvent of those examined for the extraction of 2-chlorobenzylidenemalononitrile and a range of capsaicins from "CS Gas" and '"Pepper" sprays respectively. Controlled experiments undertaken showed that capsaicins were recoverable after 72 h of exposure to the "elements" and 2-chlorobenzylidenemalononitrile was still recoverable after one week.
Lewis
K
K
Lothian and Borders Police Forensic Science Laboratory, Edinburgh, Scotland, UK.
Lewis
R J
RJ