Thiocyanate Ion Selective Solid Contact Electrode Based on Mn Complex of N,N'-BIs-(4-Phenylazosalicylidene)-O-Phenylene Diamine Ionophore

A thiocyanate ion selective poly(aniline) solid contact electrode based on manganese complex of N,N’-bis-(4-phenylazosalicylidene)-o-phenylene diamine ionophore was successfully developed. The electrode exhibits a good linear response of 58.1 mV/decade (at 20 ̊C ± 0.2 ̊C, r = 0.998) with in the concentration range of 1 × 10 ~ 1 × 10 M thiocyanate solution. The composition of this electrode was: ionophore 0.040, polyvinylchloride 0.300, dibutylphthalate 0.660 (mass). This dibutylphthalate plasticizer provides the best response characteristics. The electrode shows good selectivity for thiocyanate ion in comparison with any other anions and is suitable for use with aqueous solutions of pH 4.0 ~ 6.0. The standard deviations of the measured emf difference were ±1.70 and ±2.01 mV for thiocyanate sample solutions of 1.0 × 10 M and 1.0 × 10 M, respectively. The stabilization time was less than 170 sec. and response time was less than 17 sec.