The anion response characteristics of Salicylaldehyde-alanine-imidazole metallic complexes are described.The results show that the electrode based on Salicylaldehyde-alanine-imidazole copper（Ⅱ） [Cu（Ⅱ）-SAI] demonstrates excellent potentiometric response towards thiocyanate ion and anti-Hofmeister selectivity sequence in following order:SCN->ClO-4>Sal>I->Br->NO-2>NO-3>So-3>Cl->SO2-4>H2PO-4.The electrode shows a near-Nernstian potentiometric response to thiocyanate ion in a wide range of 1.0×10-1-3.0×10-6mol/L with a detection limit 1.0×10-6mol/L and a slope of-55.3 mV/decade in pH 5.0 of phosphate buffer solution at 20℃.The response mechanism is discussed in view of the A.C.impedance technique and the UV spectroscopy technique.The electrode exhibits the advantages of high selectivity,low detection limit,reproducibility and simplicity.The electrode was successfully applied to the determination of thiocyanate ion in waste water and human saliva.
