Pyrolysis Gas Chromatography–Mass Spectrometry for the Characterization of Tire Marks for Forensic Analysis

Pyrolysis-gas chromatography-mass spectrometry was applied to the quantitative and comparative analysis of rubber samples collected from tire marks left on different types of road surfaces. Ten types of tires were used to create skid marks. It was observed that factors such as surface type, sampling method, and the place where the sample was taken revealed no influence on chemical composition of pyrolysate. Chemical analysis of the traces left on different types of substrates allowed one to distinguish between these traces, allocate samples to different rubber classes, and to assign the trace to a particular type of tire. Application of a simple, semi-quantitative method developed to describe the composition of the samples facilitated the distinction between samples. Furthermore, in most cases, tire marks showed great consistency with the rubber taken from the respective tires.