title: Exploiting flow injection and sequential injection anodic stripping voltammetric systems for simultaneous determination of some metals.
abstract: Flow injection (FI) and sequential injection (SI) systems with anodic stripping voltammetric detection have been exploited for simultaneous determination of some metals. A pre-plated mercury film on a glassy carbon disc electrode was used as a working electrode in both systems. The same film can be repeatedly applied for at least 50 analysis cycles, thus reducing the mercury consumption and waste. A single line FI voltammetric system using an acetate buffer as a carrier and an electrolyte solution was employed. An injected standard/sample zone was mixed with the buffer in a mixing coil before entering a flow cell. Metal ions were deposited on the working electrode by applying a potential of -1.1 V vs Ag/AgCl reference electrode. The stripping was performed by anodically scanning potential of working electrode to +0.25 V, resulting a voltammogram. Effects of acetate buffer concentration, flow rate and sample volume were investigated. Under the selected condition, detection limits of 1 mug l(-1) for Cd(II), 18 mug l(-1) for Cu(II), 2 mug l(-1) for Pb(II) and 17 mug l(-1) for Zn(II) with precisions of 2-5% (n=11) were obtained. The SI voltammetric system was similar to the FI system and using an acetate buffer as a carrier solution. The SI system was operated by a PC via in-house written software and employing an autotitrator as a syringe pump. Standard/sample was aspirated and the zone was then sent to a flow cell for measurement. Detection limits for Cd(II), Cu(II), Pb(II) and Zn(II) were 6, 3, 10 and 470 mug l(-1), respectively. Applications to water samples were demonstrated. A homemade UV-digester was used for removing organic matters in the wastewater samples prior to analysis by the proposed voltammetric systems.
authors.affiliation: Department of Chemistry, Faculty of Science, and Institute for Science and Technology Research and Development, Chiang Mai University, Chiang Mai 50202, Thailand.
authors.forename: Siripat
authors.initials: S
authors.lastname: Suteerapataranon
authors.forename: Jaroon
authors.initials: J
authors.lastname: Jakmunee
authors.forename: Yuthsak
authors.initials: Y
authors.lastname: Vaneesorn
authors.forename: Kate
authors.initials: K
authors.lastname: Grudpan