New Ni(II) Ion-selective electrode based on the N-S Schiff base ligand as neutral carrier in PVC matrix

A nickel(II) [Ni(II)] ion-selective electrode was prepared by incorporating a new N-S Schiff base ligand, glyoxal-bis(S-benzyldithiocarbazate) (GBSB), as a neutral carrier into the PVC matrix. The proposed electrode exhibits an excellent near-Nernstian response for Ni2+ ions, ranging from 2.8x10-7 to 1.0x10-1mol/L with a detection limit of 1.2x10-7mol/L and a slope of 31.9 +/- 0.3mV/dec in pH 4.0 nitrate buffer solution at 25 degrees C. It has an appropriate response time and suitable reproducibility and can be used for at least 3 months. The operational pH range of the proposed electrode is 4.0-7.5. The response mechanism is discussed in view of the alternating current (AC) impedance technique. In addition, the electrode was successfully used as an indicator electrode in potentiometric titration of Ni2+ ion and in the direct determination of Ni2+ ion in milk power and chocolate samples.