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

Abstract

In a previous article, Rigano et al. established a new linear retention index system for the identification of triacylglycerols by liquid chromatography 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 mass spectrometry. 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 mass spectromtery and retention information to achieve univocal identification. With this purpose, a new software was implemented to make the identification process easy and automatic as in gas chromatography-mass spectrometry where the retention index filter is added in the spectral search to discriminate between compounds with similar mass spectrometry spectra. A total of 69 species were identified and, thanks to their baseline separation obtained by an ultra high performance liquid chromatography method, a semiquantification 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. K E Y W O R D Slinear retention index, lipids, sea bass, spectral library, triacylglycerols

Dietary Intake of Coumarins and Furocoumarins through Citrus Beverages: A Detailed Estimation by a HPLC-MS/MS Method Combined with the Linear Retention Index System

“…A new software, namely ChromLinear (Chromaleont, Messina, Italy) version 1.0, developed ad hoc for LRI database handling in LC [ 60 ], was employed for a fast and automatic peak identification. The software is able to perform a dual-filter search, thus, excluding from the list of compounds with a high spectral similarity (minimum direct and reverse match were both set at a value of 800; they are calculated based on the NIST MS search algorithm), those falling out the window of ±4 LRI units.…”

Elucidation of the Lipid Composition of Hemp (Cannabis sativa L.) Products by Means of Gas Chromatography and Ultra-High Performance Liquid Chromatography Coupled to Mass Spectrometry Detection

“…The identification was primarily performed in an automatic way by using the novel ChromLinear software, which enables a fast data processing by matching with a previously built and constantly implemented LRI database [ 18 , 19 , 43 ] and home-made MS library reported in a previous work [ 43 ].…”

“…Regarding lipid analysis, FAs are generally investigated, in form of FA methyl ester (FAME) derivatives, by gas chromatography (GC) coupled to flame ionization detection (FID) and mass spectrometry (MS), for quantitative and qualitative purposes, respectively [ 14 , 15 ]. Instead, reversed phase liquid chromatography (RP-LC) is the most suitable separation approach for complex lipid analysis, as in the case of TAGs [ 16 , 17 , 18 , 19 ]. In RP-LC, hydrophobic interactions between the target analytes and the stationary phase, normally a octadecylsilica (C18) particle packed column, provide a separation of the mixture that directly depends on the TAG partition number (PN), calculated from the equation PN = ECN = CN—2DB (equivalent carbon number, carbon chain length and double bonds number, respectively) [ 20 ].…”

Why the Stall? Using metabolomics to define the lack of upstream movement of invasive bigheaded carp in the Illinois River

“…However, there is a contrasting body of research that has found EPA can increase with water contamination [ 91 ]. Thus, the explanation for the decline in EPA in silver carp from the leading edge relative to conspecifics from downstream is not fully understood, but may in part be due to the type of contaminant(s) to which organisms are exposed [ 91 ], or food available [ 92 ], and should be investigated in future work. Together, results from this study clearly show that silver carp at the leading edge of the Illinois River have reduced levels of EPA relative to the downstream core population, possibly indicative of increased energetic demands as a result of xenobiotic exposure, and further studies are needed explain the mechanism for this finding.…”