Dual Z-Scheme Heterojunction of Nanomaterials for the Simultaneous Electrochemical Detection of Chloramphenicol and Furazolidone in Food Samples

Abstract

Advanced nanomaterials offer transformative potential in addressing food safety challenges, particularly in the detection of antibiotic residues. This study reports the synthesis of a dual Z-scheme heterojunction nanocomposite BWS/PGCN/EBS via ultrasonication for electrochemical sensing applications. The heterojunction integrates bismuth tungsten selenide (BWS) with porous graphitic carbon nitride (PGCN) as a highly conductive matrix, followed by europium bismuth selenide (EBS), with both semiconductors doped to enhance their electronic properties. This configuration facilitates efficient charge separation and favorable band alignment, significantly improving electrochemical performance. Morphological characterizations confirm the structural integrity and atomic arrangement of the composite. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and linear sweep voltammetry (LSV) reveal high sensitivity in detecting chloramphenicol (CAP) and furazolidone (FZ), both individually and simultaneously. The sensor demonstrates low detection limits of 18.91 nM for CAP and 6.49 nM for FZ when measured individually. Under simultaneous detection conditions, the limits of detection are 11.31 nM for CAP and 11.75 nM for FZ, with corresponding quantification limits of 34.29 and 35.63 nM. A linear current response is observed across analyte concentrations ranging from 10 nM to 50 nM, with calculated sensitivities of 2.66 × 10^–5 A.nM^–1.cm^–2 for CAP and 3.035 × 10^–5 A.nM^–1.cm^–2 for FZ, further validating the sensor’s quantitative performance. The sensor maintains high selectivity in the presence of common interferents and demonstrates excellent recovery rates in real food matrices, such as milk and honey. Density functional theory (DFT) studies are conducted to support the proposed redox mechanism, and the computational results correlate well with the experimental findings, confirming the sensor’s enhanced performance for FZ over CAP. This work underscores the critical role of advanced nanomaterials in developing sensitive, selective, and reliable electrochemical sensors, contributing to public health protection and the advancement of sustainable analytical technologies.