title: Solid-phase extraction and liquid chromatography--mass spectrometry for the determination of free fatty acids in shellfish.
abstract: A novel analytical protocol for the determination of free fatty acids (FFAs; saturated, monounsaturated and polyunsaturated) in shellfish using electrospray ionisation and liquid chromatography-mass spectrometry (LC-MS) is described. Total lipids were extracted from four commercially important shellfish species using chloroform-methanol in a modification of the traditionally used Bligh and Dyer method. FFAs were recovered from lipidic shellfish extracts by solid-phase extraction (SPE) on an aminopropyl-silica column using a 98:2 v/v diethyl ether (DEE)-acetic acid solution. Ether extracts containing the FFAs were evaporated and reconstituted in 70:30 v/v methanol-chloroform before analysis by LC-MS. The limits of quantification (LOQs) of the method ranged from 60 to 560 microgg(-1) wet weight depending on the different FFAs determined with selected ion monitoring (SIM). Results demonstrate that LC-MS is well suited for identification and quantification of FFAs in shellfish and negates the use of sample derivatisation required in gas chromatographic analysis.
authors.affiliation: Fisheries Research Services (FRS) Marine Laboratory, 375 Victoria Road, Aberdeen AB11 9DB, UK.
authors.forename: Jean-Pierre C L
authors.initials: JP
authors.lastname: Lacaze
authors.forename: Lesley A
authors.initials: LA
authors.lastname: Stobo
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Turrell
authors.forename: Michael A
authors.initials: MA
authors.lastname: Quilliam
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D005230:Fatty Acids, Nonesterified / Q000032:analysis* / Q000737:chemistry; D008055:Lipids / Q000737:chemistry / Q000302:isolation & purification; D013058:Mass Spectrometry / Q000379:methods*; D008974:Mollusca / Q000737:chemistry*; D015203:Reproducibility of Results; D052616:Solid Phase Extraction / Q000379:methods*
chemical_list: D005230:Fatty Acids, Nonesterified; D008055:Lipids