Thiocyanate-selective electrode based on N-salicylidene-benzylamineato copper(II) complex

Research paper by F. C. Wang, Y. Q. Chai, R. Yuan

Indexed on: 19 Jan '11Published on: 19 Jan '11Published in: Russian Journal of Electrochemistry


Highly selective poly(vinyl chloride) (PVC) membrane electrode based on N-salicylidene-benzylamineato copper(II) complexes [Cu(SBA)2] as new carriers towards thiocyanate-selective electrode was reported. The influence of membrane composition, pH and possible interfering anions were investigated on the response properties of the electrode. The resulting electrode exhibits anti-Hofmeister selectivity sequence: SCN− > ClO4− > Sal− > I− > Br− > NO3− > NO2− > SO32− > H2PO4− > Cl− > SO42−, and a near-Nernstian potential linear range for thiocyanate from 1.0 × 10−1 to 9.0 × 10−7 M with a detection limit of 7.0 10−7 M and a slope of \( - 57.5 mV/pc_{SCN^ - } \), over a wide pH range of 3.0–9.0 in phosphate buffer solution at 20°C. The proposed electrode has a fast response time of about 5–10 s and can be used for at least 3 months without any considerable divergence in potential. The electrode was successfully applied to the determination of thiocyanate in waste water and human urine and saliva samples.