title: Mass spectral characteristics of okadaic acid and simple derivatives.
abstract: Electron ionization (EI), chemical ionization (CI) and fast-atom bombardment (FAB) mass spectra of the marine toxin okadaic acid and its synthetic methyl, pentafluorobenzyl, and trimethylsilyl ester and ether derivatives were generated. Several ionization conditions and ion-processing methods were used to obtain positive- and negative-ion conventional spectra and tandem (MS/MS) spectra. The EI and the positive-ion CI spectra provided fragment ions characteristic of the structure, and the negative-ion CI and FAB spectra provided molecular ions. The addition of alkali salts to the FAB matrix resulted in reduced fragmentation and the formation of intense alkali-metal-cationized molecules. Pentafluorobenzyl ester derivatives provided intense carboxylate ions under electron-capture ionization. Analytically useful MS/MS spectra were obtained by low-energy collision-induced decomposition of the carboxylate anion produced from the tetrasilylated pentafluorobenzylokadaate.
authors.affiliation: Mass Spectrometry Center, College of Medicine, University of South Alabama, Mobile 36688.
authors.forename: F A
authors.initials: FA
authors.lastname: Bencsath
authors.forename: R W
authors.initials: RW
authors.lastname: Dickey
mesh_terms: D004988:Ethers, Cyclic / Q000032:analysis*; D008387:Marine Toxins / Q000032:analysis*; D013058:Mass Spectrometry; D019319:Okadaic Acid; D016339:Spectrometry, Mass, Fast Atom Bombardment
chemical_list: D004988:Ethers, Cyclic; D008387:Marine Toxins; D019319:Okadaic Acid