title: Direct analysis of microcystins by microbore liquid chromatography electrospray ionization ion-trap tandem mass spectrometry.
abstract: Microcystins are a group of structurally similar cyclic heptapeptide hepatotoxins and tumor promoters, produced by cyanobacteria. A microbore liquid chromatography electrospray ionization ion-trap mass spectrometry (LC-ESI-ITMS) method has been developed which is capable of separating and detecting trace amounts of microcystin variants in environmental samples. Extracted water sample was loaded onto a LC trapping column and, using a column switching technique, the compounds of interest were back-flushed onto a 1-mm LC column. Structural elucidation was achieved using ion-trap with tandem mass spectrometry in the data dependent scan mode. Collision-induced dissociation to MS3 allowed tentative identification of these cyclic peptides. Full-scan LC-ESI-MS mass spectrum was obtained when 250 pg of the authentic compound was injected onto the HPLC column, which represents the detection limit for microcystin-LR. This study demonstrated that LC-ESI-ITMS is a reliable and sensitive technique for analysing trace levels of microcystins.
authors.affiliation: Analytical Toxicology Diagnostic Laboratory , New York College of Veterinary Medicine, Cornell University, Ithaca 14850, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Zweigenbaum
authors.forename: J D
authors.initials: JD
authors.lastname: Henion
authors.forename: K A
authors.initials: KA
authors.lastname: Beattie
authors.forename: G A
authors.initials: GA
authors.lastname: Codd
authors.forename: G K
authors.initials: GK
authors.lastname: Poon
mesh_terms: D001427:Bacterial Toxins / Q000032:analysis*; D002853:Chromatography, Liquid; D000458:Cyanobacteria / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D052998:Microcystins; D010456:Peptides, Cyclic / Q000032:analysis*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D001427:Bacterial Toxins; D052998:Microcystins; D010456:Peptides, Cyclic; C078588:microcystin