关键词: 修饰电极, PVC膜修饰粉末微电极, 溶出伏安法, 微电极伏安法

Abstract: Polyvinyl chloride film powder microelectrode, which is prepared by flow spread over the powder microelectrode with the tetrahydrofuran solution of 1.5% PVCand 1% di iso octyl phthalate. When this PVCfilm is swollen in solution, it has permeability and selectivity for the substance of electrochemical activity. Cyclic voltammetry of polyvinyl chloride modified powder microelectrode in 10mmol/L K₃Fe(CN) ₆+1 mol/L KCl solution, the results show that this is semi reversible electrode process. When the scan rate of potential come up, Δ Ep increased, i_pa / i_pc becomes less and verge to 1. EK₃Fe(CN)₆/K₄Fe(CN)₆^0' _{was calculated with Epa and Epc to be +0.167 V(vs. SCE), which agreed with the standard value. This PVCfilm electrode exhibit fast response and long term stability, allowable operating potential range(potential range: +1.2～-1.2 V) and no use for mercury. It is used for work electrode in the stripping voltammetry under no strirring. In a supporting electrolyte of 0.02 mol/L HAc, anodic stripping voltammetry(ASV) for the direct determination of Pb ²⁺ in tap water. For tap water a mean value of 10⁵×10^-7 g/mL Pb ²⁺ was found, which agreed with the method of the hanging mercury drop electrode(HMDE). The relative standard deviation(n =5) for Pb ²⁺ is 1.3%. Recoveries of Pb ²⁺ in water samples are between 97.8% and 99.5%.}

Key words: Modified electrode, Polyvinyl chloride film powder microelectrode, Stripping voltammetry, Microelectrode voltammery