ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Cyclic voltammetric determination of phosphate in tap water via [Omim]₆Mo₇O₂₄-carbon paste electrodes

Jialin Zhou, Jiayu Fei, Cheng Zeng, Hong Hua Quan, and Ming Li

College of Environmental Science and Engineering, Yangzhou University, Yangzhou, People’s Republic of China

E-mail: liming@yzu.edu.cn

Received: 12 January 2023  Accepted: 31 May 2023

Abstract:

Stably retaining the water-soluble molybdate within electrodes is of great significance in phosphate analysis. This study fabricated an [Omim]₆Mo₇O₂₄ carbon paste electrode (OCPE), which was able to effectively retain molybdate in the aqueous solution. The electrochemistry of phosphate at the surface of the OCPE was studied using cyclic voltammetry (CV). The voltammograms showed three reversible redox peaks corresponding to the redox of Mo(VI/V) as well as several irreversible peaks involving the formation of hydrogen molybdenum bronze. The currents of all three reversible redox peaks linearly varied versus phosphate concentrations in 0.1 mol·L⁻¹ H₂SO₄-KCl. After optimizing the mass ratio of the [Omim]₆Mo₇O₂₄ and carbon powder, peak C6 shows a wide linear range (1.0 × 10^–2–1.0 × 10^–7 mol·L⁻¹; R² = 0.9970) with a sensitivity of 5.3 (± 0.1) μA/μM. The limit of detection (LOD = 3σ/s) was 8.5 × 10^–8 mol·L⁻¹. Interferences from common anions, silicate, and glyphosate on phosphate analysis were also investigated. The proposed sensing method was successfully applied to the determination of phosphate in tap water, whose results were verified with ion chromatography (IC).

Keywords: [Omim]6Mo7O24 electrodes; Phosphate analysis; Tap water; Cyclic voltammetry

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-023-02906-0

Chemical Papers 77 (10) 5873–5880 (2023)