Preconcentration and electroanalysis of silver species at polypyrrole film modified glassy carbon electrodes

Silver species can be entrapped in electropolymerized polypyrrole films without deliberate incorporation of chemically active counterions. The effects of polypyrrole coverage and preparation condition, oxidation states, solution composition, pH and the presence of other metal ions on the preconcentration have been investigated. Experimental results showed that the peak current and the integrated charge for incorporated silver species showed good linear concentration dependence in the range of 2-150 μM. The detection limit was estimated to be about 2 μM (about 0.2 ppm Ag). Most of the metal ions studied, including cobalt, nickel, cadmium, lead, zinc and iron, did not show obvious interference on the determination. Copper and mercury species were also extracted onto polypyrrole film electrodes and caused significant interference in the determination of silver species. The mechanism involved in the preconcentration of silver species at polypyrrole electrodes was explored.