Stripping Voltammetric Determination of Silver Ion with Modifed Carbon Fiber Electrode as Working Electrode

Method of preparation and pretreatment of carbon fiber electrode (CFE) was described,and the CFE obtained was modified by electrochemical polymerization of the monomer thiophene.In the determination of Ag+-ion,the test solution in 0.1 mol·L-1 HNO3 was pretreated by reduction for 120 s at -0.5 V,where the Ag+-ion was complexed with polythiophene.Silver ion in the complex was then stripped from the electrode by differential pulse anodic stripping voltammetry with scanning in the range from 0 to 0.6 V,and the oxidation peak potential of silver ion was observed at 0.24 V,where linear relationship between values of peak current of Ag+-ion and its concentration was obtained in the range of 5.0×10-7-1.0×10-3mol·L-1.Detection limit (3S/N) of the method found was 5.0×10-8mol·L-1.