Cetylpyridinium-tetraiodomercurate PVC Membrane Sensor for Determination of Iodide in Water Samples and Pharmaceutical Preparation

A new PVC membrane sensor for iodide has been investigated. The PVC sensor is composed of cetylpyridinium (CP) -tetraiodomercurate (HgI4-2) as counter ion in a plasticizer solvent. The PVC membrane showed a near Nernstian response in the range 1 x10(-2)M - 5 x 10(-6)M iodide at 25 degrees C with an anionic Nernstian slope of 55 +/- 0.5 mV per 10 fold. The response time and limit lower of detection are 20sec and 3 x 10(-6)M respectively. Effect of different ions on the selectivity of iodide was studied. There are negligible effects were caused by the most of the examined ions. The proposed method shows good recovery and precision values. The obtained data by the proposed method for the assay of iodide in its dosage form (gallamine triiodide) are agreed with the reported spectrofluorometric method. The suggested membrane sensor has been used as indicator sensor for determination of mercury and silver ion using potentiometric titrations.