title: Optimization of electrochemical hydride generation in a miniaturized electrolytic flow cell coupled to microwave-induced plasma atomic emission spectrometry for the determination of selenium.
abstract: The optimization of a continuous flow system for electrochemical hydride generation coupled to microwave-induced plasma atomic emission spectrometry (MIP-AES) for the determination of Se is presented. A small electrolytic cell with a porous glassy carbon working electrode was used for hydride generation. When using an Ar MIP operated in a TE101 cavity a detection limit of 0.6 ng mL(-1) (3sigma) could be achieved. The calibration curve was linear up to 1 microgram mL(-1). A standard deviation of less than 2% (10 replicate analyses) could be achieved. It was shown that interferences of transition metals are of the same order of magnitude as with a larger electrolysis cell described earlier, and light elements hardly caused any signal depression as tested. It was possible to distinguish between Se(IV) and Se(VI) species and seleno-DL-methionine, because under optimized conditions of an electrolysis current of 10 mA, a microwave power of 210 W, an Ar flow rate of 15 L h(-1) and a sample flow rate of 2.5 mL min(-1) only Se(IV) was transformed to H2Se and transferred into the plasma. Finally, the possibility of an electrochemical pre-enrichment was shown to enable it to further decrease the detection limit.
authors.affiliation: University of Leipzig, Institute for Analytical Chemistry, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Schermer
authors.forename: L
authors.initials: L
authors.lastname: Jurica
authors.forename: J
authors.initials: J
authors.lastname: Paumard
authors.forename: E
authors.initials: E
authors.lastname: Beinrohr
authors.forename: F M
authors.initials: FM
authors.lastname: Matysik
authors.forename: J A
authors.initials: JA
authors.lastname: Broekaert