| Résumé | A combined liquid chromatography/mass spectrometry (LC/MS) method using ion-spray ionization is described for the sensitive determination of okadaic acid and dinophysistoxin-1, the principal toxins implicated in cases of diarrhetic shellfish poisoning. The method is used to confirm the presence of okadaic acid in a culture of the dinoflagellate species Prorocentrum concavum and in natural populations of dinoflagellates from eastern Canadian waters. Several analogues of the toxin have also been detected. Quantitative results are comparable to those obtained by high performance liquid chromatography with fluorescence detection. With slight modifications, the LC/MS method is also used to analyse the fluorescent anthrylmethyl ester of okadaic acid. Preliminary tandem mass spectrometric results, obtained using fast-atom bombardment ionization, are presented for okadaic acid. |
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