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dc.contributor.authorMiles, Christopher O.
dc.contributor.authorSandvik, Morten
dc.contributor.authorNonga, Hezron E.
dc.contributor.authorRundberget, Thomas
dc.contributor.authorWilkins, Alistair L.
dc.contributor.authorRise, Frode
dc.contributor.authorBallot, Andreas
dc.date.accessioned2012-10-25T02:16:07Z
dc.date.available2012-10-25T02:16:07Z
dc.date.copyright2012-08-21
dc.date.issued2012
dc.identifier.citationMiles, C. O., Sandvik, M., Nonga, H. E., Rundberget, T., Wilkins, A. L., Rise, F., & Ballot, A. (2012). Thiol derivatization for LC-MS identification of microcystins in complex matrices. Environmental Science & Technology, 46(16), 8937-8944.en_NZ
dc.identifier.issn0013-936X
dc.identifier.urihttps://hdl.handle.net/10289/6740
dc.description.abstractMicrocystins are a group of cyclic heptapeptides originating from cyanobacteria. Cyanobacteria also produce a range of peptides and other compounds that can result in complex chromatograms when samples are analyzed by LC-MS. Derivatization with appropriate thiols (e.g., mercaptoethanol) of the olefin in the alpha,beta-unsaturated amide present in most microcystins was shown to simplify analysis of LC-MS chromatograms of sample extracts, making it much easier to identify peaks corresponding to candidate microcystins. Furthermore, interpretation of MS2 spectra was facilitated by addition of the mass associated with the thiol to the alpha,beta-unsaturated amide of microcystins. Cyanotoxins containing Mdha or Dha reacted readily with thiols, whereas Mser, Ser, Mdhb, and thiol-derivatives of Mdha or Dha did not react under the conditions used. This approach therefore provides a convenient LC-MS method to obtain evidence for the presence of Mdha or Dha and can likely be used to differentiate between the isobaric amino acids Mdha and Dhb in candidate cyanotoxin peaks. When O-(2-mercaptoethyl)-O'-methyl-hexa(ethylene glycol) (MEMHEG) (M(w)t. 356) was used as the thiol, the resulting derivatives eluted in an LC-MS mass window that was largely free of interferences. This approach simplifies detection of candidate microcystin analogues even in the presence of complex mixtures of coeluting components. The method was used for qualitative analysis of a Microcystis aeruginosa culture from Lake Naivasha, Kenya, and the results were verified using precursor-ion scanning and high-resolution mass spectrometry.en_NZ
dc.language.isoen
dc.publisherAmerican Chemical Societyen_NZ
dc.relation.ispartofEnvironmental Science & Technology
dc.subjecttandem mass-spectrometryen_NZ
dc.subjectstructural-characterizationen_NZ
dc.subjectheptapeptide microcystinsen_NZ
dc.subjectcyanobacteriaen_NZ
dc.subjectaeruginosaen_NZ
dc.subjecthepatotoxinsen_NZ
dc.subjectpeptidesen_NZ
dc.subjecttoxinsen_NZ
dc.subjectdecompositionen_NZ
dc.subjectderivativesen_NZ
dc.titleThiol derivatization for LC-MS identification of microcystins in complex matricesen_NZ
dc.typeJournal Articleen_NZ
dc.identifier.doi10.1021/es301808hen_NZ


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