Detection methods and their limitations:: PSP toxins in the southern puffer fish Sphoeroides nephelus responsible for human poisoning events in Florida in 2004

High-performance liquid chromatography (HPLC) with post-column derivatisation and fluorescence detection has been commonly used for analysing paralytic shellfish poisoning (PSP) toxins. However, identifying peaks with confidence requires that steps be taken beyond simple chromatographic runs, owing in part to the abundance of substances in natural samples that have intrinsic fluorescence and may co-elute with toxins. The aim of this study was to assess HPLC toxin detection in samples collected from two puffer fish poisoning (PFP) events. Since 2002, PSP toxins have been detected in southern puffer fish Sphoeroides nephelus from the Titusville region of Florida. Despite a current harvesting ban on southern puffer fish in this area, PFP reports continue. Unconsumed puffer fish from two human poisoning events in 2004 were analysed by HPLC for PSP toxins. Saxitoxin was the dominant congener in unconsumed puffers. Decarbamoyl saxitoxin and B1 were also detected. These toxins were confirmed through a series of HPLC steps and subsequently by other methods. This work serves as an example of procedures necessary for HPLC toxin detection, provides a comparison of HPLC with other detection methods, and demonstrates the continued threat of PSP toxicity associated with puffer fish from the Titusville area of Florida.