| Summary: | This study aims to complement the internationally implemented method “CEN/TR 15522-2: 2012 WATERBORNE PETROLEUM AND PETROLEUM PRODUCTS - PART 2” (CEN). It is a method for forensic investigations on oil spill identification using gas chromatography coupled with low resolution mass spectrometry in electron ionisation mode (GC-EI-MS), in single ion monitoring mode (SIM). The method uses hydrocarbon fingerprints and biomarker abundances to compare oils from spill sources with oil from suspected sources. This method is implemented by the national forensic centre (NFC) with their main object to perform and develop forensic investigations for successful law enforcement. The experiment uses four different matrices common within the NFC department: wood ash, soil, fabric and cotton swabs. The method evaluates how different sample preparation and clean-up techniques can extract crude oil and heavy fuel oil without losing important information such as the relative abundance of so-called biomarkers typically looked for in international standard praxis in forensic investigations. In conclusion the implemented CEN method showed a reasonably good extraction from matrixes. Extraction of biomarkers were generally quantitative. Extractions of PAHs worked best in soil and cotton swab matrices. In ash samples, the extraction was not very efficient (between 20-80%). It seems that the PAHs strongly bind to active coal in the ash and cannot be extracted fully. It was also evident that the fabric matrix used was problematic for PAH extraction. The fabric itself seemed to release compounds which interfere with the analysis. In soil samples, 31abR (a biomarker compound) was a reoccurring interference from the matrix. Furthermore, analysis of isoprenoids and alkanes had a very broad analytical variation, seen by that the analytical response for these compounds vary greatly among different samples. SPE-extractions did not work well enough following the protocol in this study to be included as a sample preparation step at the moment. More optimization would be needed before the method could be included as an implemented method.
|
|---|
