Construction of suitable iodide-selective electrode based on phenyl mercury (II)(2-mercaptobezothiozolate) carrier

Highly selective poly( vinyl chloride) ( PVC) membrane electrode based on recently synthesized mercury complex i.e., phenyl mercury ( II) (2-mercaptobezothiozolate) (PMMBT) as new carrier for iodide-selective electrode by incorporating the membrane ingredients on the surface of graphite electrode are reported. The effect of various parameters including the membrane composition, pH, and possible interfering anions were investigated on the response properties of the electrode. The developed sensor exhibited Nernstian responses toward iodide over a wide concentration range of 1 x 10 27 to 0.1 M with slopes of 57.6 +/- 0.8 mV per decade of iodide concentration and detection limit of 8 x 10 28 M, over a wide pH ranges of 2.0-11.5. The sensors have response time of 0.5 s and can be used for at least 2 months without any considerable divergence in their potential response. The proposed electrode show good ability to discriminate iodide over several inorganic and organic anions. The electrode was successfully applied to direct determination of iodide in synthetic mixture, waste water and drinking water, and pharmaceutical samples in addition to applying as indicator electrode in precipitation titration.