Abstract: The present paper describes a new nickel ion selective electrode with a neutral carrier, hexadecyl iso-nicotinate synthesized in our laboratory.The electrode shows a linear response to Ni²⁺ ions in the range of 10^-1 ~ 8×10^-5 mol/Lwith a slope -25.5 ± 0.4 mV/pC(20±1℃).The potentiometric selectivity coefficients for nickel ions with respect to Na⁺, K⁺, Li⁺, Ca²⁺, Sn²⁺, Fe²⁺, Co²⁺ and Cu²⁺ are 8.1×10^-5, 8.6×10^-5, 8.2×10^-5, 4.1×10^-3, 7.5×10^-4, 3.2 × 10^-2, 8.0 × 10^-2 and 4.4 × 10^-1, respectively.The electrode has a fair reproducibility and quick potential response.The conductivity mechanism of the membrane was studied with A.C.impedance method.The experimental results show that the transfer process of Ni²⁺ ions across the solvent polymeric membrane is controlled by the diffusion process.

Key words: Hexadecyl iso-nicotinate, Nickel ion selective electrode, Neutral carrier