DI(ETHYLXANTHATE) COMPLEXES OF METAL(II) AS NEUTRAL CARRIERS FOR HIGHLY SELECTIVE IODIDE ELECTRODES

The present paper describes solvent polymeric membrane anion selective electrodes based on di(ethylxanthate) complxes of metal(IT) [cobalt(I I), mercury(II) and zinc(II)] as neutral carriers. The electrode incor porating cobalt(II) - di(ethylxanthate) has high selectivity toward th e iodide ion and demonstrates anti - Hofmeister behaviour. The electro de showed a near - Nernstian potentiometric response for 10(-1) simila r to 10(-6) mol/L I- with a detection limit of 7.9 x 10(-7) mol/L and a slope of 54 mV/pI(-) (20 degrees C). The electrode has low resistanc e, fast response time, fair stability and reproducibility. The selecti vity sequence observed is iodide > thiocyanate > nitrite > bromide > p erchlorate > sulfate > nitrate > chloride. The response mechanism of t he electrode was also studied with the a. c. impedance and spectroscop ic techniques.