Desarrollo de métodos de caracterización de activadores en incendios

Abstract

The phenomenon of arson, especially forest fires, is becoming in one of the major problems facing our society. In most cases human activity was responsible for these fires. It is estimated that more than 90% of the forest fires in the world are caused by humans (intentionally or accidentally). In arson, accelerants such as ignitable liquids are commonly used to initiate or accelerate a fire. The detection of ignitable liquid residues at fire scenes is therefore a key step in fire investigations. The most widely used analytical technique for the analysis of accelerants is GC-MS. Although GCMS has proven to be useful in this field, it requires long analysis times and it cannot be applied as a screening technique or for rapid quantitative analysis. Furthermore, pre-concentration of the ignitable liquid residues is required prior to the chromatographic analysis. Consequently, the development of non-separative methods for the resolution of different analytical problems is of increasing interest. In some cases, it is sufficient to obtain a signal profile or fingerprint of the sample formed by all the components. In the work described in this thesis, an alternative analytical technique based on HS-MS eNose (headspace mass spectrometry electronic nose) is proposed for the analysis of both, neat ignitable liquids and ignitable liquids residues in fire debris. Therefore, this research project addresses independent studies: 1. Optimization of the HS-MS eNose for the discrimination of commercial gasoline samples with different research octane numbers. 2. Validation of the results by HS-MS eNose with those obtained by the reference method NIRS, for the analysis of gasoline samples with different research octane number. 3. Chemical fingerprinting of Ignitable liquids by Headspace-Mass Spectrometry eNose. 4. Optimization of an HS-MS eNose for thermal desorption of the carbon strips as an alternative to desorption with solvent. 5. Optimization of the HS-MS eNose for the analysis of ignitable liquid residues from fire debris. 6. Validation of the results by HS-MS eNose with those obtained by the reference method ASTM E1412 and ASTM E1618 for the analysis of ignitable liquid residues from fire debris.