Determination of lipophilic marine biotoxins in aquatic products by liquid chromatography coupled with triple quadrupole mass spectrometry

Lipophilic marine biotoxins include Azaspiracid-1 (AZA-1), Azaspiracid-2 (AZA-2), Azaspiracid-3 (AZA-3), Pectenotoxin-2 (PTX 2), Okadaic acid (OA), Dinophysistoxin-2 (DTX-2), Dinophysistoxin-1 (DTX-1), Yessotoxin (YTX), and 1-Homoyessotoxin (Homo-YTX) were extracted with methanol, followed by cleaning up with solid phase extraction technique (SPE). Lipophilic toxins were confirmed and quantified by liquid chromatography coupled with triple quadrupole mass spectrometry (LC/MS/MS) using calibration curves on the solvent. The quantification limits of this method satisfied the requirements of the European Maximum Residue Limit (MRLs) with 25 µg/kg for the YTX group and 10 µg/kg for AZA, OA, and PTX groups. To validate the effectiveness of this method, matrices of clams, fish, and mixed seafood were collected and analyzed (recovery ranged from 92.4 - 101.5%, and relative standard deviation was less than 20%). The method was used successfully to participate in a proficiency testing program organized by Quasimeme (z-score in the range of ±2)