Abstract

A selective electrochemical sensor for the determination of nickel (II) ions was developed using differential pulse voltammetry. The sensor was fabricated as a modified carbon paste electrode, with a composition consisting of the following percentages: (graphite powder 39.5%, dibutyl phthalate (DBP) 46.50%, sodium tetraphenylborate (NaTBPH) 7%, and Lo-Complex 7% as the active material. This formulation features (DBP) as a plasticizer to form the appropriate paste consistency, and (NaTBPH) to enhance ionic properties. To optimize the response and achieve the best analytical performance, the factors affecting the sensor’s operation were studied and evaluated. The results showed that the optimal peak current response was achieved at (pH 9.5). The use of (0.03 M) Ammounia Buffer as a supporting electrolyte proved effective in achieving the best electrical conductivity and eliminating migration current, ensuring that the analyte reaches the electrode surface controlled only by diffusion. Furthermore, the optimal accumulation conditions were determined to be a potential of (-550 mv) and an accumulation time of (300 Sec), allowing maximum deposition of nickel ions onto the modified electrode surface. Under these conditions, the sensor exhibited a high and linear current response, confirming its potential for successful application in the accurate and selective determination of nickel ions in various samples.