Liquid chromatography–electrospray ionization mass spectrometry of the diarrhetic shellfish-poisoning toxins okadaic acid, dinophysistoxin-1 and pectenotoxin-6 in bivalves

Determination of diarrhetic shellfish-poisoning (DSP) toxins, okadaic acid (OA), dinophysistoxin-1 (DTX1) and pectenotoxin-6 (PTX6) was carried out by liquid chromatography (LC) followed by on-line atmospheric pressure electrospray ionization-mass spectrometric (ESI-MS) detection with a heated capillary interface. Mass spectra of authentic OA, DTX1 and PTX6 standards exhibited abundant [M-H]− at m/z 803, 817 and 887, respectively. Linearity of peak area obtained by selected-ion monitoring (SIM) for [M-H]− of each toxin was confirmed over a wide range of concentrations from 10 pg to 30 ng. LC–ESI-MS analysis of OA, DTX1 and PTX6 in scallops and mussels, collected at the same site (Mutsu Bay, Japan), was carried out. Scallops and mussels collected at the same site showed different toxin profiles. Although PTX6 was detected from scallops, it was not detected from mussels.