An Optimized Method for the Simultaneous Analysis of 16 Lipophilic Marine Toxins Using LC-MS/MS with Solid-Phase Extraction Cleanup in Seafood Matrices

Abstract

Lipophilic marine toxins (LPMTs) are toxic secondary metabolites produced by microalgae. With rising sea surface temperatures driven by climate change, the spread of harmful microalgae is increasing. This study established and validated a simultaneous analysis method for 16 LPMTs, including compounds from the okadaic acid (OA), yessotoxin (YTX), azaspiracid (AZA), pectenotoxin (PTX), and cyclic imine (CI) groups. The method was validated in mussel, clam, and flatfish matrices and applied to seafood collected from three coastal areas in Korea (the East, West, and South Seas), to assess LPMT contamination. The limit of detection for the method was calculated to be 0.01-3.54 mu g kg-1 for all 16 toxins. Accuracy and precision were confirmed through repeated intraday and interday analyses, with all results satisfying CODEX guidelines (accuracy: 60-115%, precision: <= 22%), indicating that the method can be successfully applied to fish and shellfish matrices. From the 25 collected samples, compounds from the OA group were found in seven (28%) at a positive mean of 82.0 mu g OA eq. kg-1, YTX-group compounds were found in two (8%) at a positive mean of 224.4 mu g YTX eq. kg-1, and CI-group compounds were found in two (8%) at a positive mean of 14.3 mu g kg-1. No PTX- or AZA-group toxins were detected in any samples. LPMTs were detected in all three sea areas. The established method for the simultaneous analyses of 16 LPMTs in both bivalves and fish saves analytical time and allows proactive monitoring of regulated as well as unregulated LPMTs.