title: Quantification of volatile-alkylated selenium and sulfur in complex aqueous media using solid-phase microextraction.
abstract: Biologically produced volatile-alkylated Se and S compounds play an important role in the global biogeochemical Se and S cycles, are important constituents of odorous industrial emissions, and contribute to (off-)flavors in food and beverages. This study presents a fully automated direct-immersion solid-phase microextraction (DI-SPME) method coupled with capillary gas chromatography-mass spectrometry (GC/MS) for the simultaneous quantification of 10 volatile-alkylated Se and S compounds in complex aqueous media. Instrumental parameters of the SPME procedure were optimized to yield extraction efficiencies of up to 96% from complex aqueous matrices. The effects of sample matrix composition and analyte transformation during sample storage were critically assessed. With the use of internal standards and procedural calibrations, the DI-SPME-GC/MS method allows for trace-level quantification of volatile Se and S compounds in the ng/L range (e.g. down to 30 ng/L dimethyl sulfide and 75 ng/L dimethyl selenide). The applicability and robustness of the presented method demonstrate that the method may be used to quantify volatile Se and S compounds in complex aqueous samples, such as industrial effluents or food and beverage samples.
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600, Dübendorf, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, CH-8092, Zurich, Switzerland.
authors.forename: Bas
authors.initials: B
authors.lastname: Vriens
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600, Dübendorf, Switzerland.
authors.forename: Marcel
authors.initials: M
authors.lastname: Mathis
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600, Dübendorf, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, CH-8092, Zurich, Switzerland.
authors.forename: Lenny H E
authors.initials: LH
authors.lastname: Winkel
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600, Dübendorf, Switzerland. Electronic address: michael.berg@eawag.ch.
authors.forename: Michael
authors.initials: M
authors.lastname: Berg
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry; D018036:Selenium Compounds / Q000032:analysis*; D052617:Solid Phase Microextraction; D013455:Sulfur / Q000032:analysis*
chemical_list: D018036:Selenium Compounds; D013455:Sulfur
keywords: GC/MS; Methylation; SPME; Selenium; Sulfur