Arson can result in highly challenging and complicated crime scenes. Much physical evidence undergoes chemical degradation because of the destructive nature of fire, while accelerants either completely burn or evaporate, and may be present in traces within any of the decomposed materials. To identify the original material and the accelerant involved, it is necessary to use advanced analytical techniques. Gas chromatography, with different detectors, is one of the most frequently used instruments in fire debris and accelerant analysis. Among other instruments, capillary electrophoresis and laser-induced thermal desorption Fourier transform mass spectrometry are two major contributors. Vibrational spectroscopy, including infrared absorption and Raman scattering, is one of the major non-destructive tools for the analysis of evidence because of its advantages over other spectroscopic techniques. Most studies involving vibrational spectroscopy (i.e. infrared and Raman spectroscopy) have focused on the identification of commonly found household materials, while very few studies have considered the identification of ignitable liquids. This article reviews studies based on an analysis of fire debris and accelerants by vibrational spectroscopic techniques and considers the limitations and future perspectives of arson investigations in forensic science.

Forensic investigation of arson residue by infrared and Raman spectroscopy: From conventional to non-destructive techniques.

Publisher Summary This chapter discusses the chemical analysis of fire debris for potential accelerants The chemical analysis of fire debris is complicated and fraught with unexpected surprises In many ways, the final result is only as strong as the weakest link in the overall procedure It is always necessary to improve instrumentation to make up for weaknesses in other parts of the analytical scheme Advances in the quality of chromatographic separations and in mass spectral selectivity are certainly promising avenues Moreover, advances in separations technology have briefly been discussed in the chapter dealing with chromatography Comprehensive two-dimensional gas chromatography (GC) with mass spectrometry (MS) detection has an almost unlimited potential to characterize the composition of complex samples The chapter explains that improvements are also possible in mass spectrometry As in GC, selectivity can be enhanced by adding another dimension MS/MS is a technique in which mass spectrometry is carried sequentially GC/MS/MS appears to be a very complicated process, and indeed, it is It requires a suitable instrument that can perform sequential ionization and mass analysis

Chapter 18 The chemical analysis of fire debris for potential accelerants

This review gives a brief overview of developments in the analysis of petroleum products (PP) in fire debris residues (FDR) by gas chromatography (GC) The review covers different aspects of analysis such as the substrates involved, isolation procedures, column and mobile phase used, and subsequent detection in tabular form This paper covers detection of PP such as petrol, kerosene, and diesel in various types’ of samples of interest to fire debris analysts Solid phase microextraction is most frequently used along with gas chromatography-mass spectrometry (GC-MS) for the extraction and identification of PP from FDR Chemometric tools should be used to improve the significance and reliability of results obtained from the analysis of FDR However, the potential utility of portable GC-MS in fire debris analysis cannot be ignored, and its proper development and validation is required before using it for this purpose

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Analysis of Petroleum Products in Fire Debris Residues by Gas Chromatography: A Literature Review

Fire accelerant classification from GC-MS data of suspected arson cases using machine-learning models.

Polymerised styrene-butadiene rubber (SBR) 1502 is one of the most common petrochemical products. During the identification of fire evidence, the combustion residues of SBR 1502 highly interfere with the identification of gasoline, a fire accelerant. By conducting thermogravimetric–differential scanning calorimetry (TG-DSC) experiments at various oxygen concentrations (0, 14, and 21 vol.%), the TG-DSC combustion characteristic behaviour of SBR 1502 was investigated. Gas chromatography–mass spectrometry was used to examine the combustion residues at different stages. The results indicated a lack of 2,3-dimethylnaphthalene among the combustion residue of SBR 1502 at the oxygen concentration of 0 and 14 vol.%, thus effectively avoiding the interference of this combustion residue in gasoline identification. The results of the quantitative analysis revealed aromatic hydrocarbon components as the most interfering components for all oxygen concentration and temperature. The combustion residues of SBR 1502 at different oxygen concentrations and combustion stages exhibited different degrees of interference in gasoline identification. Therefore, qualitative and quantitative analyses (hierarchical clustering analysis) were employed to eliminate interference from SBR 1502 in gasoline identification. The results provide theoretical support during the fire identification process.

K.A. Ambade

Papers

Detection of petroleum accelerant residues on partially burnt objects in burning/arson offences