01993nam a2200205   4500001000700000100004100007101000800048200010600056210002900162215003700191300022300228330119000451606002201641606001501663606002101678606002901699606002901728606000901757700002101766392325  a20140120d2012       y0pory50      ba  aeng  aEvaluation of cross-contamination of nylon bags with heavy loaded petrol fire debrisfFilipa Belchior  aLancashirec[s.n.]d2012  axiii, 116, [38] p. anexosd30 cm  aSubmitted (September 2012) in partial fulfilment of the requirement for the degree of Masters of Science in Fire Investigation - School of Forensic and Investigative Sciences - University of Central Lancashire (UCLan).  aThe integrity of evidence is extremely important in forensic science and in the judicial system to avoid miscarriages of justice. Contamination and cross-contamination must be prevented. Evidence should be packed in a container that prevents loss or addition to the material. Nylon bags are the most used container for fire debris evidence in the UK and are also used in several European countries. Cross-contamination of nylon bags in normal casework conditions was studied, using heavy loaded petrol fire debris and using automotive topcoat thinner (oxygenated solvent). Samples were sealed with swan-neck with plastic cable ties in both ends and were stored in crates, typically used in the UK to transport evidence from the fire scene to the laboratories. The analyses were performed using gas chromatography / mass spectrometry. Cross-contamination was found for petrol in the two brands of nylon bags used, after significantly different periods of time. In both brands the same aromatic compounds were identified. Cross-contamination was also found using automotive topcoat thinner and using only one brand of bags. Oxygenated compounds and one aromatic compound were identified.  aCIÊNCIA FORENSE  aINCÊNDIO  aRECOLHA DA PROVA  aANÁLISE DE VESTÍGIOS  aPRESERVAÇÃO DA PROVA  aTESE  aBELCHIORbFilipa