title: Nano liquid chromatography with hybrid quadrupole time-of-flight mass spectrometry for the determination of yessotoxin in marine phytoplankton.
abstract: Studies of yessotoxin involving confirmation of fragmentation processes using a high-resolution orthogonal hybrid quadrupole time-of-flight (QqTOF) mass spectrometer and nanoLC hybrid quadrupole TOF MS have been undertaken. The fragmentation of YTX was studied in negative mode using nano electrospray (nanoESI) QqTOF mass spectrometry. Three major molecule-related ions were observed, [M - 2Na + H]-, [M - Na]- and [M - 2Na]2-, and fragmentation of the latter was studied in detail. This showed that product ions were formed as a consequence of charge-remote fragmentation processes that included a strong directional cleavage of the polyether rings of YTX. NanoLC coupled with QqTOF MS was used to determine YTX in small samples of the phytoplankton, Protoceratium reticulatum, by monitoring the [M - 2Na]2- ion at m/z 570. A PepMap C18 nanoLC column (75 microm x 10 cm, 100 A, 3 microm, LC Packings) was used and the solvent was acetonitrile/water (90:10 (v/v)) containing 1 mM ammonium acetate, at a flow rate of 400 nl/min, for 30 min. Calibrations obtained with YTX standard solutions were linear over four orders of magnitude, 0.75-250 ng/ml; r2 = 0.9947-0.9998. Phytoplankton cells (ca. 100-300) were picked, extracted with methanol/water (40:60), and the YTX concentration was determined over the range 0.011-0.020 ng/cell. The detection limit (3 x S/N) of this method was ca. 0.5 pg YTX on-column.
authors.affiliation: PROTEOBIO, Mass Spectrometry Centre for Proteomics and Biotoxin Research, Department of Chemistry, Cork Institute of Technology, Bishopstown, Cork, Ireland.
authors.forename: Isabel
authors.initials: I
authors.lastname: Ruppén Cañás
authors.forename: Brett
authors.initials: B
authors.lastname: Hamilton
authors.forename: Mónica
authors.initials: M
authors.lastname: Fernández Amandi
authors.forename: Ambrose
authors.initials: A
authors.lastname: Furey
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: James
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D004988:Ethers, Cyclic / Q000032:analysis*; D008386:Marine Biology; D013058:Mass Spectrometry / Q000379:methods*; D008978:Mollusk Venoms; D036103:Nanotechnology; D035964:Oxocins / Q000032:analysis*; D010839:Phytoplankton / Q000737:chemistry*
chemical_list: D004988:Ethers, Cyclic; D008978:Mollusk Venoms; D035964:Oxocins; C066632:yessotoxin