The Genoa 2005 Outbreak. Determination of Putative Palytoxin in Mediterranean Ostreopsis ovata by a New Liquid Chromatography Tandem Mass Spectrometry Method

A new method for sensitive, specific and direct determination of palytoxin is proposed herein. It is based on combination of reversed phase liquid chromatography with mass spectrometry (LC-MS). The new method was set up on a turbo ionspray (TSI)-triple quadrupole MS instrument operating in selected ion monitoring (SIM) and multiple reaction monitoring (MRM) acquisition modes (positive ions). The minimum detection levels for matrix-free toxin on column were thus estimated from the data to be 200 pg and 125 pg in SIM and MRM mode, respectively. Spiking experiments before and after extraction allowed to assess limits of detection and quantitation for palytoxin in matrix, accuracy, intra-day and inter-day reproducibility of the method. The developed method was decisive for the analysis of a plankton sample collected along Genoa coasts in July 2005 when respiratory illness in people exposed to marine aerosols occurred. It allowed to suggest that putative palytoxin was the causative agent responsible for patients’ symptoms and demonstrated for the first time the presence of such a toxin in Italian waters.