title: Online preconcentration-IC-ICP-MS for selenium quantification and speciation at ultratraces.
abstract: Selenium (Se) is of key importance to human health with a very narrow concentration range of optimal dietary intake. Due to the inherent analytical challenge linked with the low natural abundance, information on precise and accurate Se speciation in deficient environments is hardly existent. This study presents a novel approach to determine Se species-specifically at ultratraces, by online coupling of a preconcentration (trap) column to an ion chromatography inductively coupled plasma mass spectrometry (IC-ICP-MS) system. It is demonstrated that with this robust and work/time efficient method, the predominant selenium oxyanions, selenite (Se(IV)) and selenate (Se(VI)), can be quantified down to 7.3 and 8.3 picogram total Se, respectively, in an overall analytical time of 420 s, only. The applicability for environmental samples was proven on pristine volcanic ashes collected from seven different volcanoes. The high sensitivity of the novel approach allowed to determine speciation in samples that were strongly depleted in total selenium (<0.05 mg kg(-1) Se) with only minor fractions of Se mobilized (i.e., less than 10% of the total selenium was leached in 10 out of 12 samples). The studied samples showed considerate differences in selenium speciation, with selenite and selenate co-occurring in most samples. The fact that the studied sample leachates had a wide range of pH (3.78-9.55) and major anion/cation composition underlines the versatility and wide potential application range of the method presented.
authors.affiliation: Institute for Ecopreneurship, University of Applied Sciences and Arts Northwestern Switzerland (FHNW), School of Life Sciences, Gründenstrasse 40, 4132 Muttenz, Switzerland. Markus.Lenz@fhnw.ch
authors.forename: Markus
authors.initials: M
authors.lastname: Lenz
authors.forename: Geerke H
authors.initials: GH
authors.lastname: Floor
authors.forename: Lenny H E
authors.initials: LH
authors.lastname: Winkel
authors.forename: Gabriela
authors.initials: G
authors.lastname: Román-Ross
authors.forename: Philippe F X
authors.initials: PF
authors.lastname: Corvini
mesh_terms: D004784:Environmental Monitoring / Q000379:methods*; D013058:Mass Spectrometry / Q000379:methods*; D009862:Online Systems; D064586:Selenic Acid; D012643:Selenium / Q000032:analysis*; D018036:Selenium Compounds / Q000032:analysis; D018038:Sodium Selenite / Q000032:analysis
chemical_list: D018036:Selenium Compounds; D012643:Selenium; D018038:Sodium Selenite; D064586:Selenic Acid