Quantitative determination of marine lipophilic toxins in mussels, oysters and cockles using liquid chromatography-mass spectrometry: inter-laboratory validation study

Abstract

Thirteen laboratories participated in an inter-laboratory study to evaluate the method performance characteristics of a liquid chromatography-tandem mass spectrometric method (LC-MS/MS) for marine lipophilic shellfish toxins. Method performance characteristics were evaluated for mussel (Mytilus edulis), oyster (Crassostrea gigas) and cockle (Cerastoderma edule) matrices. The specific toxin analogues tested included okadaic acid (OA), dinophysistoxins-1 and -2 (DTX1, -2), azaspiracids-1, -2 and -3 (AZA1, -2, -3), pectenotoxin-2 (PTX2), yessotoxin (YTX), and 45-OH-yessotoxin (45-OH-YTX). The instrumental technique was developed as an alternative to the still widely applied biological methods (mouse or rat bioassay). Validation was conducted according to the AOAC-harmonised protocol for the design, conduct and interpretation of method–performance studies. Eight different test materials were sent as blind duplicates to the participating laboratories. Twelve laboratories returned results that were accepted to be included in the statistical evaluation. The method precision was expressed as HORRATs. For the individual toxins (except for 45-OH-YTX) HORRATs were found to be ≤1.8 (median HORRAT = 0.8) in all tested materials. The recoveries of OA-, AZA- and YTX-group toxins were within the range of 80–108% and PTX2 was within the range of 62–93%. Based on the acceptable values for precision and recovery, it was concluded that the method is suitable for official control purposes to quantitatively determine OA/DTXs, AZAs, YTXs and PTX2 in shellfish.

Keywords:

• LC/MS
• inter-laboratory validation
• phycotoxins
• DSP
• natural toxicants
• seafood

Acknowledgements

The authors would like to thank the participating institutes: CER – Centre d’Economie Rurale (Marloie, Belgium); IPH – Scientific Institute of Public Health (Brussels, Belgium); IFREMER – Institut français de recherche pour l’exploitation de la mer (Nantes, France); BfR – Bundesinstitut für Risikobewertung (Berlin, Germany); Chemical and Veterinary Analytical Institute (Muenster, Germany); Marine Institute (Oranmore, Ireland); Centro Ricerche Marine (Cesenatico, Italy); Norwegian School of Veterinary Science (Oslo, Norway); IRTA – Agencia Española de Seguridad Alimentaria y Nutrición (Tarragona, Spain); CEFAS – Centre for Environment, Fisheries & Aquaculture Science (Weymouth, UK); AFBI – Agri-Food and Biosciences Institute (Belfast, UK); and NOAA – National Oceanic and Atmospheric Administration (Charleston, NC, USA). The authors also thank the EU-RL on Marine Biotoxins (Vigo, Spain), because of its continuous support in the preparation and organisation of this study. The authors thank the collaborators: M. Andjelcovic, B. Ben-Gigirey, S.M. O’Brien, P. Delahaut, G.J. Doucette, D.V. Faulkner, F. Herve, P. de la Iglesia, O. Keuth, A. Milandri, S. Morris, L.T.T. Nguyen and A. These.