Amperometric detection studies of poly-o-phenylenediamine film for the determination of electroinactive anions in ion-exclusion chromatography

An amperometric detector based on the chemical modification of poly-o-pheny lenediamine (P-OPD) on a gold electrode was successfully used for the deter mination of electroinactive anions (SO42-, Cl-, NO3-, F-, CH3COO- and PO43- ) by single-column ion-exclusion chromatography. All of the anions were det ected conveniently and reproducibly in a linear concentration range of 1.0 x 10(-5)-5.0 x 10(-3) mol L-1. The detection limits of the anions were 2.10 x 10(-6) mol L-1 for SO42-, 2.47 x 10(-6) mol L-1 for Cl-, 3.53 x 10(-6) m ol L-1 for NO3-, 3.41 x 10(-6) mol L-1 for F-, 5.82 x 10(-6) mol L-1 for CH 3COO- and 3.86 x 10(-6) mol L-1 for PO43- at a signal-to-noise ratio of 3. The proposed method was successfully applied to the analysis of rainwater a nd river water samples. The electrode was stable during a 2 week period of operation with no evidence of chemical or mechanical deterioration.