Determination and confirmation of the amnesic shellfish poisoning toxin, domoic acid, in shellfish from Scotland by liquid chromatography and mass spectrometry

During 1998 and early 1999, shellfish samples from sites in Scotland were f ound to contain the amnesic shellfish poisoning toxin, domoic acid (DA). Tw o different techniques, liquid chromatography (LC) with UV diode-array dete ction and LC with mass spectrometric (MS) detection, were used to detect an d confirm DA in shellfish extracts. The LC/UV method was validated for rout ine monitoring by recovery experiments on spiked mussel and scallop tissues with a certified mussel tissue used as reference material. Crude extracts of selected samples as well as extracts cleaned with strong anion exchange (SAX) were analyzed by both LC/UV and LC/MS. Good correlation (linear regre ssion r(2) = 0.996, slope = 0.93) between the 2 methods was found for clean ed extracts. Analyses of crude extracts by LC/UV produced false-positive re sults in 2 crab samples, whereas LC/MS analyses gave accurate results. It w as concluded that LC/UV is a valid approach for routine monitoring of DA in shellfish when cleanup is performed with a SAX cartridge to prevent false positives. A variety of shellfish species were surveyed for DA content, inc luding Pecten maximus (king scallops), Chlamys opercularis (queen scallop), Mytilus edulis (blue mussels), Cancer pugaris (crab), and Ensis ensis (raz or fish). The highest concentration of DA was 105 mug/g in Pecten maximus.