Potentiometric Phosphate Ion Sensor Based on Electrochemical Modified Tungsten Electrode

Kebin Xu; Ying Li; Min Li

doi:10.1021/acsomega.1c00195

Potentiometric Phosphate Ion Sensor Based on Electrochemical Modified Tungsten Electrode

ACS Omega. 2021 May 20;6(21):13795-13801. doi: 10.1021/acsomega.1c00195. eCollection 2021 Jun 1.

Authors

Kebin Xu^{1

2}, Ying Li^{1

2}, Min Li^{1

2}

Affiliations

¹ School of Metallurgy, Northeastern University, Shenyang 110819, People's Republic of China.
² Liaoning Key Laboratory for Metallurgical Sensor Material and Technology, Shenyang 110819, People's Republic of China.

Abstract

Determination of phosphate ions in aqueous solutions attracts a great deal of interest in the areas of environment, medicine, and agriculture. As phosphoric acid is a poly basic acid, the different forms of existence at different pH result in direct determination facing a big challenge. Herein, we reported a potentiometric phosphate ion sensor based on a surface-modified tungsten electrode. Pure tungsten was electrodeposited at a constant potential of 0.2 V versus Ag|AgCl in Na₂HPO₄. WO₃ and H₃O₄₀PW₁₂·xH₂O were electrodeposited on the surface of the tungsten electrode. The modified tungsten electrode was used as a working electrode in a two-electrode system to detect the concentration of phosphate ions in aqueous solutions. The detection limit of the modified tungsten electrode for phosphate ions is 10^-6 M from pH 7 to pH 8 and 10^-5 M from pH 9 to pH 10. It has good selectivity to other common anions. The long-term monitoring experiment showed that the potential fluctuation was less than ±3 mV in 24 h. Compared to conventional determination methods, the current phosphate ion sensor showed a close value in a real sample. The mechanism of phosphate ion response was investigated in detail. This sensor possesses advantages of simple manufacture, low cost, a wide pH range for detecting, and good selectivity.