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(II) [cobalt(II), mercury (II) andzinc(II)] as neutral carriers. The electrode incorporating cobalt(II) - di(ethylxanthate) has high selectivity toward the iodide ion and demonstrates anti - Hofmeister behaviour. The electrode showed a near - Nernstian potentiometric response for 10-1 ~ 10-6mol/L I- with a detection limit of 7. 9 × 10-7mol/L and a slope of 54 mV/pI- (20℃). The electrode has low resistance, fast response time, fair stability and reproducibility. The selectivity sequence observed is iodide thiocyanate nitrite bromide perchlorate sulfate nitrate chloride. The response mechanism of the electrode was also studied with the a. c. impedance and spectroscopic techniques.