Adsorption/Desorption GC Assisted with Retention Index Comparison of Peaks for the Identification of Accelerants in Fire Residues

This paper presents both an efficient sample preparation procedure and a highly discriminating gas chromatographic method for the identification of accelerants in fire residues. A purge-and-trap concentrator fitted with a carbotrap adsorbent tube was used to preconcentrate the accelerants from various fire residues. The resultant sample tubes were submitted to a thermal desorption unit (TDU) which was connected to a dual wide-bore capillary column GC. The identification of the accelerants was based on both retention indices comparison and chromatogram pattern recognition. The advantages and disadvantages of this dynamic adsorption/desorption procedure were discussed by comparison with other pretreatment procedures such as charcoal tube adsorption/CS, extraction and continuous steam distillation.