Preconcentration and Determination of Metal Species at Polypyrrole Modified Glassy Carbon Electrodes

Metal species can be extracted/preconcentrated onto electropolymerized polypyrrole film electrodes without deliberate incorporation of chemically active counterions. Silver species preconcentrated on polypyrrole film can be determined electrochemically. The effects of polypyrrole film coverage, electropolymerization conditions,solution composition and the presence of other species have been investigated. Experimental results showed that the anodic peak current for incorporated silver species was proportional to silver concentration in solution in the range from 2 to 150 μM. The detection limit was estimated to be about 0.2 \μM (20 ppb). Most of the metal ions studied, including Ni, Cd, Pb, Zn and Fe, did not show obvious interference on the determination. Cu and Hg were also extracted onto polypyrrole film electrodes. Polypyrrole film electrodes were reuseable. The mechanism involved in the preconcentration was also investigated.