A novel Fe2O3@DCTA-Ag nanocomposite sensor for lead detection: Box-Behnken design optimization and real-world applications

Lead (Pb²⁺) contamination poses serious risks to human health and environmental safety, highlighting the need for sensitive and selective detection methods. In this study, we developed a novel nanocomposite, Fe₂O₃ nanoparticles functionalized with 4-(3,5-dimethyl-1H-pyrazol-1-yl)carboxylate (DCTA) and decorated with silver nanoparticles (Fe₂O₃@DCTA-Ag), using simple and efficient synthesis techniques. This material was employed to fabricate an electrochemical Pb²⁺ sensor based on differential pulse voltammetry (DPV). The sensor performance was optimized using a response surface methodology (RSM) combined with a Box-Behnken design (BBD), evaluating the effects of pH, contact time, drop volume, and drying time through a 3⁴ factorial design. A multivariate regression model correlated the peak current with these factors, identifying the optimal conditions. Under these conditions, the sensor exhibited a linear detection range of 0.2 nM to 10 μM, with a detection limit of 0.2 nM. It showed excellent selectivity against co-existing ions and consistent performance in various food samples (rice, corn, milk, honey, tea) and environmental water samples, demonstrating its practical applicability.