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Lipid profile of fish species by liquid chromatography coupled to mass spectrometry and a novel linear retention index database.

In a previous paper, Rigano et al. established a new linear retention index system for the identification of triacylglycerols by LC methods only on the basis of the retention behavior and independently from many experimental parameters. In that work, a database of 209 compounds was built, but only 54 of them, typical of vegetable oils, were confirmed by MS. The aim of the present research is to extend the applicability of the novel approach to more complex samples, such as fish lipid extracts, and assess the complementarity between MS and retention information to achieve univocal identification. To this purpose, a new software was implemented to make the identification process easy and automatic as in GC-MS where the retention index filter is added in the spectral search to discriminate between compounds with similar MS spectra. A total of 69 species were identified and, thanks to their baseline separation obtained by an ultra HPLC method, a semi-quantification was also performed. The species under investigation were Dicentrarchus labrax, coming from aquaculture and the wild. Some differences in their native lipid composition were observed, probably related to a different diet. A major number of samples would be necessary to confirm such a preliminary finding. This article is protected by copyright. All rights reserved.