Stable isotope profiling of burnt wooden safety matches

Arson is a significant problem around the world, and is a crime which results in a low number of convictions. The scene of an arson can be varied, commercial, residential or national park, and recently cases have been identified which were initiated by a lit match. Matches can be recovered from a scene, usually in a burnt condition. The benefit of analysing unburnt matches has been researched previously [1,2]. In most cases, burnt matches are recovered from scenes, and therefore the research was extended to investigate the potential of using IRMS to analyse burnt matches. This includes samples which have been exposed to petrol, and various fire extinguishing chemicals. Matches were sectioned to reveal central unburnt portions of wood and analysed by isotope ratio mass spectrometry (IRMS). The stable isotope profile (SIP) of the wooden matchstick samples was unaffected by the presence of both petrol and a variety of fire extinguisher chemicals. Any changes seen could be attributed to the natural variability of isotopic composition encountered in a natural material such as wood. These findings were confirmed by the isotope analysis of 19 matchstick samples placed in mock fire training scenarios. The data was examined using a paired t-test and Hotellings T test for a single sample.