Mass Spectrometry Based Methods for the Structural Characterization of Marine Toxins

Many instrumental techniques are currently employed to identify marine toxins and characterize their structures, with nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) being the most popular and powerful. Although NMR is the technique of choice to fully elucidate stereostructure of new molecules, its applicability depends on availability of g to mg amounts of pure compound. This is often difficult to achieve in the field of marine toxins, which are usually present at sub-mg levels in complex matrices in the form of a wide array of different congeners. So recently, several MS based approaches have been developed to disclose the presence of toxins and to elucidate their structures based on the interpretation of their fragmentation pattern. This chapter provides with an overview of the different experimental strategies used to discover and elucidate the structure of marine toxins. Practical examples of how some structurally complex toxins - palytoxins, yessotoxins, and spirolides - have been studied until final characterization are included.