Sustainable Precursor-Based Titanium Dioxide–Graphene Nanocomposite Electrochemical Sensor for Sensitive Detection of Diuron in Vegetables

The persistent presence of pesticide residues in vegetables raises significant concerns for food safety and public health, highlighting the need for sensing platforms that are efficient, affordable, and environmentally friendly while minimizing analysis time and reagent use. In this study, we developed a laser-induced graphene electrode (LIGE) modified with a titanium dioxide–Enteromorpha-derived carbon composite (TiO2@EDC) for the sensitive electrochemical detection of the herbicide diuron in vegetables. This integrated system streamlines material synthesis, electrode fabrication, and electrochemical analysis into a single, practical platform for food safety monitoring. Under optimized conditions, this sensor exhibited a wide linear detection range of 0.01 µM to 1 mM, with a low limit of detection of 2.99 nM (3 S/N) and a limit of quantification of 9.98 nM (10 S/N). Notably, the sensor demonstrated excellent analytical performance in real vegetable samples by accurately quantifying diuron residues in lettuce, indicating its potential for on-site monitoring of pesticide contamination in food matrices to ensure food safety.