Sulfate-selective PVC membrane electrodes based on a derivative of imidazole as a neutral carrier Original Research Article

A sulfate-selective PVC membrane electrode has been developed using a derivative of imidazole as a neutral carrier. The behavior of the electrode is closely related to the pH values in sample solutions. The electrode shows a linear response towards sulfate in the range 3.16×10−5–0.5 mol/l in a KH2PO4–H3PO4 buffer at pH 3.06±0.01 with a slope of −28.5 mV/dec., the response mechanism of the electrode was investigated by the use of a.c. impedance and the influence on the electrode performances by lipophilic charged additives. The electrode was applied to the determination of sulfate in pharmaceutical samples and the titration of barium acetate with satisfactory results.