Time since discharge of pistols and revolvers

The estimation of time since the latest discharge of pistols and revolvers has been achieved by the Solid Phase Microextraction (SPME) sampling technique and the GC/TEA analytical system. The TEA2 compound, which in our previous work (1) was observed in barrels of shotguns and rifles as well as inside spent cartridges, was also detected in pistols and revolvers. The amount of this compound was very low in short-barreled small arms and its escape from the barrel could generally be measured for only a few days or up to two weeks after the latest discharge. To improve the detection of TEA2 compound, the SPME sampling time was prolonged and fibers coated by Carboxen/polydimethylsiloxane were used. The decrease of the TEA2 peak with time after shooting from pistols is nonexponential but the curve-fitting procedure proposed for the estimation of time since discharge of shotguns and rifles is difficult to apply as the decay is very rapid. Therefore, the detection of TEA2 compounds in small arms should be interpreted that the firearm had been used very recently. The amount of volatile decomposition products of smokeless powder increased significantly with the length of the barrel when firearms of the same caliber, but with different barrel lengths were investigated.