Voltammetric analysis of As3+ and sulfamethoxazole on an electrode modified with a composite of carbon dots and graphitic carbon nitride

Abstract

The need to monitor priority pollutants in the aqueous environments cannot be overemphasised. Herein, we employed a glassy carbon electrode (GCE) modified with a nanocomposite of carbondots (CDs) and graphitic carbon nitride (g-C₃N₄) for the determination of arsenic(III) and sulfamethoxazole (SMX) in aqueous media. The composite material, synthesised by microwave technique, was characterised by transmission electron microscopy and X-ray diffraction. The electrochemical behaviours of the modified glassy electrode were also investigated using cyclic voltammetry (CV) and differential pulsed voltammetry. The findings indicated that the constructed g-C₃N_{4/CDs/GCE electrode markedly improved the oxidation peak currents of both analytes,} suggesting enhanced sensitivities. Notably, the working ranges and detection limits obtained for arsenic (III) were 2 – 10 and 1.64 μM and 0.3 – 0.1 and 0.10 μM for SMX, respectively. Though, copper, cadmium, lead and zinc were observed to interfere with the determination of As³⁺, but EDTA was used to mask these interfering effects of the cations. The modified electrode (g- C₃N_{4/CDs/GCE) was used to quantify arsenic and SMX in spiked aqueous solution by standard} addition and percentage recoveries of 98–100% and 80–105% were recorded for As³⁺ and SMX respectively. Thus, the findings of this study established that the investigated nanocomposite material represents an easy and sensitive platform for the determination of As³⁺ and SMX in the aqueous environments to curb environmental pollution.