Gas Chromatography-Mass Spectrometry: Application of New Findings in Analyzing Organochlorine Contaminants in a Candidate Food Reference Material

Organochlorines are common toxic contaminants in the food chain, especially in aquatic biota, thus leading the world population to undesired exposures. The chemical analyses of such trace pollutants may represent a challenge: if not properly conducted, they could suffer from great uncertainties. In the present work, a new candidate reference material of oyster tissue was analyzed for the content of organochlorines. This was done within the H2020 project PRO-METROFOOD to which 17 European Countries participated. Our laboratory strictly applied the international guidelines on the subject. Even by following the recommended guidelines, however, it is difficult to analyze some Polychlorobiphenyls (PCBs). The chromatographic coelution of Polychlorobiphenyls with the same degree of chlorination or coelutions between Polychlorobiphenyls different for one chlorine only (isobaric interferences), for example, is to be cited. For a reliable quantification, therefore, we usefully exploited some innovative findings recently made by us in the field of mass spectrometry: they allowed to achieve an optimum accuracy in the case of isobaric interferences so ensuring that a correct food safety assessment is carried out. When Polychlorobiphenyls are analyzed, there are a number of good reasons for maintaining the use of the electron capture detection (ECD) in combination with the mass spectrometry. However, the present study highlights the limits and the critical points of the approach using ECD only, as many laboratories do.