Facile synthesis of petal-like VS2 anchored onto graphene nanosheets for the rapid sensing of toxic pesticide in polluted water

Abstract

Fenitrothion (FT) is a toxic phosphorothioate insecticide that can easily contaminate aquatic environments, leading to a detrimental effect on the aquatic species and harmful endocrine disrupter effects on human health. Therefore, it is vital to develop a reliable methodology for the accurate and precise real-time sensing of carcinogenic FT in water samples at trace concentration to ensure environmental safety. We aim to fabricate the low-cost VS2-attached reduced graphene oxide (RGO) sheets via a simple hydrothermal approach. It was further applied for the rapid and accurate sensing of toxic FT. The VS2/RGO-composite delivers a more favorable microenvironment for the rapid electrocatalytic sensing performance towards toxic FT reduction than the VS2 and RGO modified electrodes. The electron transfer rate constant (ks) and the saturating absorption capacity (Γ) value of FT was evaluated to be 1.52 s−1 and 2.18 × 10−10 mol cm−2, respectively. The constructed sensor exhibits a wide linear relationship after amperometry between the cathodic current densities and the concentrations of FT in the range of 5–90 nM and high sensitivity (5.569 μA nM−1 cm−2); moreover, the detection limit was 0.07 nM (S/N = 3). The fabricated sensor has excellent anti-interference ability and reproducibility for the direct sensing of FT in river water, seawater, and lake water samples with acceptable recoveries. It is a promising sensing device for in-situ quantification of FT in agricultural products and ecological systems.

Keywords

• electrochemical sensor
• reduced graphene oxide
• amperometry
• composite
• fenitrothion