Development of a manganese dioxide solid-phase reactor for oxidation of toxins associated with paralytic shellfish poisoning

Using manganese dioxide as a solid-phase oxidant, a post-column HPLC reactor for paralytic shellfish poison toxins was constructed and evaluated. Operating parameters such as reaction temperature and pH, flow-rate, reactor column size, and MnO2 particle size were studied. Based on a 3:1 signal-to-noise ratio, the limits of detection for the non-hydroxylated toxins were in the sub-nanogram range, while the hydroxylated toxins were ten times less detectable. The limit of detection for saxitoxin was about 0.1 ng per injection. The repeatability of replicate injections was less than or equal to 10% (relative standard deviation). The system was used to analyze extracts of shellfish and plankton, yielding results that were in agreement with those obtained by established analytical methods. Extracts of shellfish contaminated at the regulatory limit of 0.8 mu g/g were successfully analyzed.