Time since discharge of rifles

The estimation of time since the latest discharge of rifles has been achieved by the SPME sampling technique and the GC-TEA analytical system. An unidentified compound, designated as the TEA2 compound, was detected in all the rifles investigated. The same compound was observed in shotguns and spent cartridges in our previous work. This compound escapes rapidly from the inside of rifle barrels, but can still be detected there one to two months after the shooting. The decrease of the TEA2 peak with time after shooting is non-exponential, and the curve-fitting procedure proposed for the estimation of time since discharge of shotguns can be applied also for rifles.