Influence of the extraction procedure on recovery of okadaic acid from experimentally contaminated mussels

Hepatopancreas samples from mussels ( Mytilus galloprovincialis) experimentally contaminated with okadaic acid were analysed with Yasumoto's mouse bioassay and HPLC. A likely effect of some components of the hepatopancreas on the results (matrix effect) was evaluated, and a possible loss of toxin during the extraction phase was quantified. Experiments were conducted by comparing two different extraction procedures. Under our experimental conditions, the results obtained from mouse bioassay showed no matrix effect with either procedure. A certain quantity of the actual amount of okadaic acid contained in the sample was found to be lost after the extraction i.e. 10.2–17.0% in samples extracted with acetone alone and 9.8–18.5% in samples extracted with acetone and ether.