title: A flow injection biosensor system for highly sensitive detection of 2,4,6-trichlorophenol based on preoxidation by ceric sulfate.
abstract: A flow injection biosensor system was proposed for the highly sensitive detection of 2,4,6-trichlorophenol (2,4,6-TCP). The system is based on the preoxidation by ceric sulfate to the corresponding benzoquinone (2,6-dichloro-1,4-benzoquinone: 2,6-DC-1,4-BQ), which was characterized using cyclic voltammetry, hydrodynamic voltammetry, and UV-vis spectrophotometry. The laccase-based biosensor used in this analytical system responded sensitively to 2,4,6-TCP after the preoxidation by ceric sulfate. The response could be based on the bioelectrocatalytic recycling of oxidation product (2,6-DC-1,4-BQ) between laccase membrane and the electrode, because the oxidation product (2,6-DC-1,4-BQ) of 2,4,6-TCP was an electrochemically reversible redox species. The signal current was linearly related to the 2,4,6-TCP concentrations in a dynamic range of 2 nM - 2 microM; the slope and the y-intercept of the straight line were 1150 nA microM(-1) and 0.88 nA, respectively. The detection limit was 1.2 nM (S/N = 3) for a 20 microl injection. Among a variety of chlorophenols and some phenolic compounds, the only interferent was 2,4-dichlorophenol.
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuencho, Sakai, Osaka 599-8531, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Yao
authors.forename: Kazuya
authors.initials: K
authors.lastname: Kotegawa
mesh_terms: D015374:Biosensing Techniques; D002138:Calibration; D002733:Chlorophenols / Q000032:analysis* / Q000737:chemistry; D017022:Flow Injection Analysis; D007202:Indicators and Reagents; D042845:Laccase; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry; D010636:Phenols / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D013464:Sulfuric Acids / Q000737:chemistry*
chemical_list: D002733:Chlorophenols; D007202:Indicators and Reagents; D010636:Phenols; D013464:Sulfuric Acids; C042259:ceric sulfate; D010088:Oxidoreductases; D042845:Laccase; C024564:2,4,6-trichlorophenol