This paper describes a potentiometric titration using a modified pencil graphite electrode with polypyrrole (PGE/PPyCl) for determination of halides at low concentrations (ppm). This indicator electrode was prepared using a pencil graphite electrode coated with a thin polypyrrole conducting polymer film and its recognition property for halides was investigated. The polypyrrole (PPy) film was prepared by the electropolymerization of pyrrole monomer in the presence of NaCl as supporting electrolyte using a pencil graphite electrode (PGE) as working electrode. The PGE/PPyCl electrode was then used as indicator electrode for determination of halide ions via potentiometric precipitation titration with silver ion. The titration curves were compared with those obtained by a normal silver wire indicator electrode. It was found that using PGE/PPyCl provides higher precision and lower detection limit in measurement of halide ions.
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