title: Microfluidic Separation of Redox Reactions for Coulometry Based on Metallization at the Mixed Potential.
abstract: Coulometric detection of an analyte in a solution at nanoliter scale was conducted by having redox reactions proceed simultaneously on a platinum electrode. The analyte was oxidized on a part of the electrode in one flow channel and silver was deposited on an array of circular microelectrodes formed in another flow channel at a mixed potential. Coulometric determination of the deposited silver showed a steep change in the generated charge as a result of the complete oxidation of silver. The short measurement time after the start of the coulometry suppressed the increase in background charge, resulting in significant lowering of the detection limit. The lower detection limit for H2O2was 30 nM (3σ). To improve selectivity and minimize the influence of coexisting interferents, the shifting of the mixed potential, application of a permselective membrane, and electrochemical elimination of the interferents were effective modifications.
authors: Graduate School of Pure and Applied Sciences, University of Tsukuba , 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan.
authors: Kazuhiro
authors: K
authors: Ikemoto
authors: Graduate School of Pure and Applied Sciences, University of Tsukuba , 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan.
authors: Takafumi
authors: T
authors: Seki
authors: Graduate School of Pure and Applied Sciences, University of Tsukuba , 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan.
authors: Shohei
authors: S
authors: Kimura
authors: Graduate School of Pure and Applied Sciences, University of Tsukuba , 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan.
authors: Yui
authors: Y
authors: Nakaoka
authors: Graduate School of Pure and Applied Sciences, University of Tsukuba , 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan.
authors: Shinnosuke
authors: S
authors: Tsuchiya
authors: Graduate School of Pure and Applied Sciences, University of Tsukuba , 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan.
authors: Fumihiro
authors: F
authors: Sassa
authors: Graduate School of Pure and Applied Sciences, University of Tsukuba , 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan.
authors: Masatoshi
authors: M
authors: Yokokawa
authors: Graduate School of Pure and Applied Sciences, University of Tsukuba , 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan.
authors: Hiroaki
authors: H
authors: Suzuki