A mussel tissue certified reference material for multiple phycotoxins. Part 2: liquid chromatography-mass spectrometry, sample extraction and quantitation procedures.

A freeze-dried mussel tissue certified reference material (CRM-FDMT1) containing multiple groups of shellfish toxins has been prepared. Toxin groups present in the material include okadaic acid and the dinophysistoxins, azaspiracids, yessotoxins, pectenotoxins, spirolides and domoic acid. In this work, analytical methods have been examined for the characterisation of the candidate CRM. A comprehensive extraction procedure was developed, which gave good recovery (>98%) for all lipophilic toxins studied. A fast liquid chromatography-mass spectrometry (LC-MS) method was developed that separates the major toxins according to the MS ionisation mode of optimum sensitivity. Matrix effects associated with analysis of these extracts using the developed LC-MS method were assessed. Standard addition and matrix-matched calibration procedures were evaluated to compensate for matrix effects. The methods and approaches will be used for the precise characterisation of the homogeneity and stability of the various toxins in CRM-FDMT1 and for the accurate assignment of certified values. The developed methods also have excellent potential for application in routine regulatory monitoring of shellfish toxins.