A potentiometric phosphate ion sensor based on electrochemically modified nickel electrode

Abstract

The effective detection of phosphate ions is very important in the fields of chemistry, biology, medicine, environment and industry. At present, the detection of phosphate ion mainly depends on molybdenum blue colorimetry. Although this method is accurate, it needs sample pretreatment, complex operation and high cost. Therefore, it is urgent to design and develop a phosphate ion sensor with high efficiency, accuracy, simple operation and real-time on-line detection. In this study, a phosphate ion sensor was designed and developed by electrochemical modification based on nickel metal electrode. Nickel electrode was specifically modified to form a phosphate of Ni on the surface of Ni electrode. The phosphate ion response of Ni-PME(Nickel-phosphate modified electrode) was evaluated in a two-electrode system. The results show that under the condition of pH 4, Ni-PME can respond to phosphate ions with a concentration of 10−5 M to 0.1 M, the response slope is −81.0 mV dec−1, and the selectivity coefficients for common anions are below −2. The response time is less than 20 s. The stability of electrode potential is very high, and the fluctuation of 24-hour continuous test potential is within ± 3 mV. The lifetime is more than 4 weeks. Compared with the traditional molybdenum blue colorimetry, Ni-PME showed good accuracy and good recovery rate.