Quali-quantitative determination and structural characterization of microalgal toxins in environmental matrices

The other extracts did not contain any PLTX congener. Molecular analyses showed that Ostreopsis sp. from Lebanon and from Cyprus Island are actually the same species that we named Ostreopsis fattorussoi. LC-HRMS analysis of Ostreopsis spp. strains from New Zealand and Australia showed that none of the known PLTX congeners so far known were contained in any of the extracts. Only a new analogue, was present in one of the Ostreopsis sp. extracts. It presented a C5H7ON moiety as well as 2 unsaturation less than OVTX-a. An extensive LC-HRMSn study, allowed to locate such modification in the very limited region stretching from the A-side terminal to C-8. This compound presented a characteristic fragmentation behavior: indeed, a formaldehyde loss could be observed from the precursor ion as well as from most of the A-side fragment ions. Formaldehyde losses may occur when a CH2OH moiety is present in the molecule following a Mac Lafferty-like rearrangement. We located the CH2OH moiety on the terminal amide. Chapter 6 reports on a survey of phytoplankton and algal toxins in Nigerian coastal waters. Seawater samples were obtained from four sites for phytoplankton identification (Bar Beach and Lekki in Lagos State, Port Harcourt in Rivers State and Uyo in Akwa Ibom State), on three occasions between the middle of October 2014 and the end of February 2015. The phytoplankton community was generally dominated by diatoms and cyanobacteria; however, several species of dinoflagellates were also identified: Dinophysis caudata, Lingul