Identification of samples of oil related to two spills

Abstract

Three samples of oil collected from an oil slick in the North Sea off the Norwegian coast, and one sample collected from the shore were all shown to come from the Claymore pipeline oil spill, which occurred in the British sector of the North Sea 26–28 November, 1986. Two other samples of oil from the Norwegian coast were shown to have a different source. A method based on separation of the aliphatic fraction of the oil followed by gas chromatography with mass spectrometric detection of polycyclic alkanes of low volatility was used for the identification. Of the polycyclic aliphatics, the pentacyclic triterpanes, as mass spectrometrically detected by the fragments m/z 191 and m/z 177, were found to be more suitable for the identification purpose than the steranes. This method was also used in another oilspill case which showed that two samples of oil from the shore of a Norwegian fjord originated from a small industrial spill.