Improved Accuracy of GC-MS Quantification of Aliphatic and Aromatic Hydrocarbons in Marine Sediments and Petroleums. Validation on Reference Matrices and Application to the Erika Oil Spill

Abstract

A rapid and simple analytical procedure allowing accurate quantification of aliphatic and aromatic hydrocarbons in sediments and petroleum has been developed. Sediments were Soxhlet extracted using methylene chloride for 48 h. Oil maltene fractions were isolated by asphaltene precipitation in pentane. Sediment and oil extracts were first purified using alumina micro-columns. Saturated fractions were then separated from aromatic ones by fractionation on silica gel. Alkanes and polycyclic aromatic hydrocarbons (PAHs) were analyzed separately by gas chromatography coupled to mass spectrometry (GC-MS). PAHs and alkanes were quantified relative to perdeuterated PAHs and alkanes introduced prior to extraction. For accurate quantification, it is important to use several perdeuterated alkanes that cover the volatility range of alkanes of interest and at least one perdeuterated PAH per class of aromaticity. This analytical procedure has been validated on a reference material sediment (SRM 1941a) and a reference material crude oil (SRM 1582). This analytical procedure was then applied to the study of the contamination of marine sediments collected along the Atlantic coast after the Erika oil spill (December 1999).