Stability of explosive residues in methanol/water extracts, on alcohol wipes and on a glass surface

The stability of four target organic explosives [pentaerythritol tetranitrate (PETN), 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and triacetone triperoxide (TATP)] and two inorganic anions (chlorate and nitrate) on polyester-based alcohol wipes and in 60% (v/v) methanol/water extracts, stored over 30 days in clear and amber glass vials at three different temperatures, was investigated in order to establish storage recommendations. The retention of all six representative compounds on a glass surface at two different storage temperatures was also included as a preliminary study on the stability of explosive residues on stored exhibits (such as post-blast debris). The results from the stability study suggested that, after sampling, the wipes should be stored in a dark and low temperature environment. Also, after extracting the wipes with 60% (v/v) methanol/water (as in our previously reported recommended protocol), the extracts should be stored in a similar fashion. The results from the retention study on the glass substrate suggested that exhibits should be stored at the lowest temperature possible to minimise the loss of TNT or TATP (or similar target compounds) that might be present as residues.