Polycyclic aromatic hydrocarbon 13C/12C ratio measurement in petroleum and marine sediments application to standard reference materials and a sediment suspected of contamination from the Erika oil spill.

This paper describes a simple and rapid sample preparation procedure allowing to measure the stable carbon isotopic composition of polycyclic aromatic hydrocarbons (PAHs) in petroleum and in sediments. The aromatic fraction is first purified and isolated on alumina and silica micro-columns. A high-performance liquid chromatography fractionation allows one then to isolate each aromatic family in order to limit coelutions between PAHs. Moreover, this purification step reduces the importance of the unresolved complex mixture which otherwise contribute to the GC-isotope ratio MS background signal. The application of this analytical procedure has allowed one to determined PAH isotopic composition in a reference material crude oil (SRM 1582) and a marine sediment (SRM 1944) with good reproducibility as uncertainties between three independent assays performed were lower than 0.5 per thousand. This analytical procedure has then been successfully applied to confirm the contamination of a sediment by the petroleum product spilled by the Erika tanker after its wreck on 12 December 1999 close to the Atlantic Coast of France.