Non-target analysis of organohalogenated contaminants in deep-sea fishes from the Mediterranean Sea by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry.

The enhanced separation power and identification capabilities make comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC - ToF MS) a valuable instrumental alternative for non-target analysis (NTA). In the present study, GC × GC - ToF MS has been used for the NTA of chlorine- and bromine-containing compounds in composite livers of two scarcely investigated Mediterranean deep-sea fish species, hollowsnout grenadier (Coelorinchus caelorhincus) and roughsnout grenadier (Trachyrhinchus trachyrhinchus). Attention focused on the identification of organohalogenated compounds with structural characteristics similar to those of persistent organic pollutants (POPs). In total, 116 Cl-, Br- and mixed Cl/Br-compounds were either positively or tentatively identified in the analyzed liver samples. Up to 88 of these compounds were legacy POPs, being polychlorinated biphenyls (PCBs) and organochlorinated pesticides (OCPs) the most abundant and frequently detected families. The other 28 identified POP-like compounds were analytes not considered by current regulation and environmental monitoring programs, including, among others, degradation products of specific OCPs, naturally produced organohalogen compounds and several perchlorinated diethyldiphenylmethane-derivatives whose presence in the investigated species is reported here for the first time. The presence of other naturally occurring brominated and mixed halogenated compounds in these fish species is also described for the first time. Our results also showed differences in the accumulation profile of the identified compounds in both species. Thereby, anthropogenic POPs showed higher relative abundances in the livers of roughsnout grenadiers than those in hollowsnout grenadiers, while for naturally occurring compounds the opposite trend or similar levels were found in both species.