EVALUATION OF A POSTCOLUMN ELECTROCHEMICAL REACTOR FOR OXIDATION OF PARALYTIC SHELLFISH POISON TOXINS

A liquid chromatographic method using a postcolumn electrochemical rea ctor that oxidizes paralytic shellfish poison toxins to fluorescent de rivatives has been developed. Several experimental parameters, includi ng pH and oxidation potential, were investigated. For nonhydroxylated toxins, the sensitivity improved with increasing pH and voltage. At op timum operating conditions, the sensitivity for saxitoxin and gonyauto xins 2 and 3 was an order of magnitude greater than that for neosaxito xin and B1 and 2 orders of magnitude greater than that for B2. The lim it of detection for saxitoxin was 0.10 ng (signal-to-noise ratio, 3:1) . Electrochemical oxidation products were similar to those formed in t he prechromatographic periodate oxidation method. Shellfish and plankt on extracts were analyzed with the electrochemical system, and results agreed well with those obtained with established methods. Shellfish s amples contaminated at the regulatory limit of 0.8 mu g/g were readily analyzed by the method.