CARCINOGENIC ASSESSMENT OF PETROLEUM-PRODUCTS BY NUCLEAR-MAGNETIC-RESONANCE

A method is proposed for improving the assessment of carcinogenicity o f petroleum materials by non-animal test means. The proposed method is an extension of the current EU regulatory test method IP 346 which me asures a proportion of the polycyclic aromatic compounds present, but does not discriminate between the carcinogenic and the non-carcinogeni c species, sometimes resulting in false positive assessments. The prop osed method involves the use of high-field proton NMR spectrometry on the IP 346 solvent extract to measure the level of 'bay region hydroge ns' within polycyclic aromatic molecules. These are structures within the molecule, considered to be directly associated with their carcinog enic potential. Tests on a wide range of petroleum materials using thi s proton NMR method show that the bay region hydrogen measurement give s greater discrimination between carcinogenic and non-carcinogenic mat erials than IP 346. The NMR method has not so far given any of the fal se positives which occur with IP 346 for oils which are not found to b e carcinogenic by bioassay. It may also be possible to use the bay reg ion hydrogen measurement as a marker for carcinogenicity in a range of petroleum products which are outside the scope of IP 346.