An electrochemical sensor derived from Cu-BTB MOF for the efficient detection of diflubenzuron in food and environmental samples

[Display omitted] •Cu-BTB was used as a precursor by calcination to obtain a porous derivative Cu/Cu2O/CuO@C with a core–shell structure.•A novel electrochemical sensor, Cu/Cu2O/CuO@C/GCE, was constructed for the detection of non-electroactive diflubenzuron.•The constructed electrochemical sensor Cu/Cu2O/CuO@C/GCE could be used for quantitative detection of diflubenzuron in real samples. Diflubenzuron is widely used as a benzoylurea insecticide, and its impact on human health should not be underestimated. Therefore, the detection of its residues in food and the environment is crucial. In this paper, octahedral Cu-BTB was fabricated using a simple hydrothermal method. It served as a precursor for synthesizing Cu/Cu2O/CuO@C with a core–shell structure through annealing, creating an electrochemical sensor for the detection of diflubenzuron. The response of Cu/Cu2O/CuO@C/GCE, expressed as ΔI/I0 exhibited a linear correlation with the logarithm of the diflubenzuron concentration ranging from 1.0 × 10−4 to 1.0 × 10−12 mol·L−1. The limit of detection (LOD) was determined to be 130 fM using differential pulse voltammetry (DPV). The electrochemical sensor demonstrated excellent stability, reproducibility, and anti-interference properties. Moreover, Cu/Cu2O/CuO@C/GCE was successfully employed to quantitatively determine diflubenzuron in actual food samples (tomato and cucumber) and environmental samples (Songhua River water, tap water, and local soil) with good recoveries. Finally, the possible mechanism of Cu/Cu2O/CuO@C/GCE for monitoring diflubenzuron was thoroughly investigated.