Isolation and purification procedures for the preparation of paralytic shellfish poisoning toxin standards

Paralytic shellfish poisoning (PSP) is caused by mixtures of saxitoxin analogs of which more than eighteen are known. Reliable and sensitive analytical methods and assays for these toxins are essential to protect the consumer and the shellfish industry, but research has been restricted by a shortage of the pure compounds. Only saxitoxin has so far been generally available as a PSP toxin standard, yet sulfated analogs usually occur in higher concentrations than saxitoxin in toxic marine algae and shellfish. Methods are described for the purification of some of the common PSP toxins, in quantities sufficient for the preparation of PSP standards from the dinoflagellate Alexandrium excavatum, the giant sea scallop (Placopecten megallanicus) hepatopancreas, and the cyanobacterium Aphanizomenon flos-aquae. Purity was monitored by high performance liquid chromatography with fluorescence detection (HPLC-FD), ionspray mass spectrometry (ISP-MS), capillary electrophoresis (CE), and proton NMR spectroscopy.