title: Identification of trace levels of selenomethionine and related organic selenium species in high-ionic-strength waters.
abstract: A new anion-exchange chromatographic separation method was used for the simultaneous speciation analysis of selenoamino acids and the more ubiquitous inorganic selenium oxyanions, selenite and selenate. For quantification, this separation was coupled to inductively coupled plasma-mass spectrometry to achieve an instrumental detection limit of 5 ng Se L(-1) for all species. This chromatographic method was also coupled to electrospray tandem mass spectrometry to observe the negative ion mode fragmentation of selenomethionine and one of its oxidation products. Low detection limits were achieved, which were similar to those obtained using inductively coupled plasma-mass spectrometry. An extensive preconcentration and cleanup procedure using cation-exchange solid-phase extraction was developed for the identification and quantification of trace levels of selenomethionine in environmental samples. Preconcentration factors of up to five were observed for selenomethionine, which in addition to the removal of high concentrations of sulphate and chloride from industrial process waters, allowed for an unambiguous analysis that would have been impossible otherwise. Following these methods, selenomethionine was identified at an original concentration of 3.2 ng Se L(-1) in samples of effluent collected at a coal-fired power plant's biological remediation site. It is the first time that this species has been identified in the environment, outside of a biological entity. Additionally, oxidation products of selenomethionine were identified in river water and laboratory algal culture samples. High-resolution mass spectrometry was employed to postulate the chemical structures of these species.
authors.affiliation: Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, K9J 7B8, Canada. kellyleblanc@trentu.ca.
authors.forename: Kelly L
authors.initials: KL
authors.lastname: LeBlanc
authors.affiliation: Thermo Fisher Scientific, 265 Davidson Avenue, Suite 101, Somerset, NJ, 08873, USA.
authors.forename: Josef
authors.initials: J
authors.lastname: Ruzicka
authors.affiliation: Water Quality Centre, Environmental and Resource Sciences Program, and Department of Chemistry, Trent University, 1600 West Bank Drive, Peterborough, ON, K9J 7B8, Canada.
authors.forename: Dirk
authors.initials: D
authors.lastname: Wallschläger
mesh_terms: D000838:Anions; D002852:Chromatography, Ion Exchange / Q000379:methods*; D005618:Fresh Water / Q000032:analysis* / Q000737:chemistry; D057230:Limit of Detection; D016566:Organoselenium Compounds / Q000032:analysis; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D064586:Selenic Acid / Q000032:analysis; D018036:Selenium Compounds / Q000032:analysis; D012645:Selenomethionine / Q000032:analysis* / Q000737:chemistry; D052616:Solid Phase Extraction; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D000838:Anions; D016566:Organoselenium Compounds; D018036:Selenium Compounds; D012645:Selenomethionine; D064586:Selenic Acid
keywords: Chromatographic interferences; Electrospray tandem mass spectrometry; Inductively coupled plasma-mass spectrometry; Organoselenium; Preconcentration; Selenoamino acids