"Atti del XXIV Congresso della Divisione di Chimica Analitica della Societ? Chimica Italiana"

A comprehensive risk management related to human exposure to cyanotoxins is limited by feasible analytical tools for monitoring non target algal metabolites. Two analytical approaches based on a liquid chromatography(LC)-Quadrupole-Time of Flight (QTOF) system for the trace determination of freshwater cyanotoxins with and without standards is here presented. A database with more than 150 compounds belonging to several classes of cyanobacteria metabolites, mainly microcystins, has been implemented for the target and non target analysis. The database has been used for a post-run data analysis according a two-steps protocol involving a) the identification of suspect cyanotoxins from their respective accurate (<30 ppm) molecular ions and b) the confirmation of the compound structure via high resolution mass spectrometric (MS) fragmentation in full scan mode. Alternatively, an automatic MSMS scan using the developed database as a preference list of precursor ions, can ensure all MS structural information in a single chromatographic run. Twenty four extract of surface waters and drinking waters contaminated by cyanobacteria have been processed. These methods allowed the confirmation of target cyanotoxins by comparison with the certified standards, as well as non target detection and characterization of five uncommon variants of microcystins and four anabaenopeptins, two of them as isobaric compounds, fully separated by the LC system. These different approaches could be used by environmental and health agencies for analyzing cyanotoxins not yet regulated in all matrices, i.e. water, air, food and biological samples, that could be contaminated by cyanobacteria.