Silver particles-modified carbon paste electrodes for differential pulse voltammetric determination of paraquat in ambient water samples

Peer review under responsibility of University of Bahrain.

Abstract

This paper describes the construction of silver particles-impregnated carbon paste electrode (Ag-CPE). The new electrode revealed an interesting determination of paraquat (II). The latter was accumulated on the modified electrode surface by adsorption onto silver particles and was reduced in 0.1 mol L⁻¹ of Na₂SO₄ electrolyte at −0.70 V and −1.0 V for peaks 1 and 2, respectively. Experimental conditions were optimized by varying the heating temperature of the silver/carbon composite, the Ag/CP ratio, pH of measuring solution and accumulation time. Under the optimized working conditions, calibration graphs were linear for the concentration ranging from 1.0 × 10⁻⁷ to 1.0 × 10⁻³ mol L⁻¹ with detection limits (DL, 3σ) 3.3 and 6.4 × 10⁻⁹ mol L⁻¹, respectively, for peaks 1 and 2. The precision of this methodology was evaluated for eight successive measurements of the same samples containing 1.0 × 10⁻⁴ mol L⁻¹ of paraquat. The relative standard deviations (D.S.R.) were 1.9% and 2.4% for the peaks 1 and 2, respectively. The Ag/CP composite was characterized by X-ray diffraction (XRD) and BET adsorption analysis.

Keywords:

• Silver
• Paraquat
• Water
• Differential pulse voltammetry

Acknowledgement

The research described in this article has been funded wholly by the University Hassan 1, Morocco.

Notes

Peer review under responsibility of University of Bahrain.