Determination of Palytoxins Oxidation Products in Seafood Using Solid Phase Extraction and Liquid Chromatography-Tandem Mass Spectrometry

Palytoxins (PlTX) belong to a group of emerging biotoxins produced by different species of corals, microalgae, and cyanobacteria. This group of toxins has a high molecular weight (~2600 Da) and is considered one of the most complex and toxic non-proteic aquatic substances. Regulatory limits for PlTXs in food samples have not yet been set. Nonetheless, the European Food Safety Authority (EFSA) has proposed a provisional limit of 30 μg PlTXs kg−1 based on the acute reference dose (ARfD). Analytical methods must be selective to discern between the various PlTX analogs and sufficiently sensitive to cover the range of interest. Analytical techniques, such as LC-MS/MS, have been powerful in the detection and quantification of PlTX. However, the lack of analytical standards for all representatives and the complexity of analyzing the intact molecules can lead to identification errors and low sensitivity. An alternative is to investigate the products resulting from the oxidation of these molecules by periodic acid, which allows the identification of characteristic molecular fragments for the main representatives of this group of toxins.