Simultaneous determination of okadaic acid, dinophysistoxin-1, dinophysistoxin-2, and dinophysistoxin-3 using liquid chromatography-tandem mass spectrometry in raw and cooked food matrices

Abstract

Diarrheic shellfish poison produced by toxic algae (e.g., Dynophysis sp.) adversely affects humans and marine ecosystems. Contamination occurs mainly from bivalve mollusks like mussels, but contamination from fishes (e.g., flatfish) has also recently been reported. Herein, we validated a liquid chromatography-tandem mass spectrometry-based analytical method for identifying okadaic acid (OA), dinophysistoxin-1 (DTX1), dinophysistoxin-2 (DTX2), and dinophysistoxin-3 (DTX3) in mussels, clams, and flatfishes, and their cooked matrices. The limits of both detection and quantification were 0.2–5.1 μg/kg. The accuracy and precision determined from intra- and inter-day repeated analyses for all matrices were 80.5%–109.8% and 0.9%–20.1%, respectively, satisfying all the performance criteria for the analytical method. The relative measurement uncertainty was estimated to be 17.8–40.8% in all matrices. Trueness was confirmed using mussel matrix certified reference material, the measurement value of which was within the certified value range. OA, DTX1, and DTX3 were detected in four mussels, two clams, and one processed case by applying the validated analytical method to commercially available samples (n = 32). In particular, DTX3 was identified in Korean mussels and clams for the first time. This method can be used to control the safety of raw and cooked bivalves and fishes from contamination with OA group toxin.