Novel thiocyanate ion-selective electrodes based on a copper(II) complex of p-hydroxyacetophenone thiosemicarbazone as a carrier

A complex of copper(II) with p-hydroxyacetophenone thiosemicarbazone has been used to fabricate a polymeric membrane electrode (PME) and coated glassy carbon electrode (CGCE). The proposed electrodes showed excellent response characteristics to thiocyanate ions over a wide concentration range from 1.0 x 10(-7) to 1.0 x 10(-1) M for PME and 1.0 x 10(-6) to 1.0 x 10(-2) M for CGCE. Nernstian slopes exhibited were -59.7 +/- A 0.3 mV decade(-1) for PME and -53.6 +/- A 0.4 mV decade(-1) for CGCE with low detection limits of 4.3 x 10(-8) and 4.1 x 10(-7) M, respectively. The PME membrane electrode provides a more sensitive and stable device than the CGCE electrode. The PME has a wide functional pH range (2.5-10.5), fast response time (5 s), and could be used for approximately 4 months without any considerable divergence in the potential. The selectivity coefficient was determined by a matched potential method and fixed interference method. A good discriminating ability towards the SCN- ion compared to other anions has been observed. PME was successfully applied as an indicator electrode for potentiometric titration of thiocyanate ion with AgNO3. Further, the electrode was successfully applied to determine the thiocyanate content in physiological fluids (urine samples).