title: Fish contamination by polychlorobiphenyls: the mass spectrometric ortho effect in a new and easy gas chromatography-mass spectrometry method for the analysis of the seven indicators. The case of Bluefin Tuna.
abstract: A simple instrumental procedure was developed to carry out the not simple analysis of PCBs in fish samples. PCBs with the same degree of chlorination (the isomers) are expected to be totally indistinguishable among them by all existing detectors and by all existing mass spectrometers, and there is no apparent solution in those frequent cases where two isomers chromatographically coelute. Generally such coelutions are solved by means of multidimensional GC, but it is a complex technique impractical for most laboratories. The present research focuses on the seven important "indicator PCBs" by using the mass spectrometer in an innovative way. The "mass spectrometric ortho effect" was usefully exploited in addressing coelutions between isomers. Other new important observations on mass spectra were decisive in solving the apparent problem arising from coelutions between higher chlorinated PCBs with the lower chlorinated ones when low-resolution MS is used. With the proposed procedure, the seven indicators are analyzed in a simple way and with a degree of accuracy never observed with the conventional gas chromatography. The method was applied to some Bluefin Tuna fish samples of big size suspected to have not negligible levels of PCBs due to the high position of this species in the food chain. The supposition was partly confirmed. On the basis of the results here obtained, the recently introduced EU Regulation on six of the seven indicators shows one critical point: in the present paper, an amendment to the Regulation is proposed. A number of important validation measures are reported.
authors.affiliation: Consiglio per la Ricerca e la Sperimentazione in Agricoltura Research Centre for Food and Nutrition, Rome, Italy. Electronic address: maurizio.masci@entecra.it.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Masci
authors.affiliation: Consiglio per la Ricerca e la Sperimentazione in Agricoltura Research Centre for Food and Nutrition, Rome, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Orban
authors.affiliation: Consiglio per la Ricerca e la Sperimentazione in Agricoltura Research Centre for Food and Nutrition, Rome, Italy.
authors.forename: Teresina
authors.initials: T
authors.lastname: Nevigato
mesh_terms: D000818:Animals; D004785:Environmental Pollutants / Q000032:analysis*; D005396:Fish Products / Q000032:analysis*; D005506:Food Contamination; D005519:Food Preservation; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D014413:Tuna
chemical_list: D004785:Environmental Pollutants; D011078:Polychlorinated Biphenyls
keywords: Bluefin Tuna (Thunnus thynnus); Coelution of isomers; EU (European Union) Regulation; Gas chromatography–mass spectrometry (GC–MS); Mass spectrometric ortho effect; Polychlorobiphenyls (PCBs)