PVC-based cobalt and manganese phthalocyanine coated graphite electrodes for determination of thiocyanate

Thiocyanate selective electrodes were prepared by incorporating cobalt and manganese phthalocyanines into plasticized ploy(vinyl chloride) membranes which were directly coated on the surface of graphite electrodes. A calibration plot with Nernstian slope for thiocyanate was observed over a linear range of five decades of concentration (1x10(-6)-1x10(-1) M). The electrode has a fast response time, very low detection limit (5x10(-7) M thiocyanate), is easy to prepare, and could be used for over a month. The proposed sensor revealed good selectivity for thiocyanate over several anions and could be used over a wide pH range. Applications of the electrode to the potentiometric titration of silver ion with thiocyanate and determination of thiocyanate in urine samples are reported.