[Occurrence and determination of okadaic acids in mussels from the German North Sea coast].

A method for the determination of okadaic acid, a typical DSP toxin, in mussels is described. The homogenized hepatopancreas is extracted and the crude extract purified by liquid/liquid partition chromatography. The derivatization of okadaic acid to 9-anthrylmethyl-okadaic acid (9-AM-OA) is achieved using the derivatization reagent 9-anthryldiazomethane (ADAM) and the clean-up is carried out by SPE with silica gel. 9-AM-OA is determined by HPLC using a RP-18 column with CH3CN/THF/H2O as the eluent. The selective and sensitive detection of 9-AM-OA is performed by coupling UV and fluorimetric detectors (detection limit: 0.5 microgram okadaic acid/g hepatopancreas).