3D Flower-Like Bi2O2CO3/2D rGO composite modified with GCE for electrochemical nanomolar quantification of chloramphenicol in biological and environmental matrices

3D/2D Bi 2 O 2 CO 3 /rGO composites were synthesized successfully. • Bi 2 O 2 CO 3 /rGO/GCE were used for high-sensitive electrochemical CAP detection. • Wide linear range (0.001–100 μM) and low LOD of 0.362 nM (S/N = 3) are obtained. Chloramphenicol (CAP) remains prevalent in aquaculture despite its classification as a Group 2 A carcinogen. Given the associated health risks, establishing robust detection methods for CAP is imperative. Herein, we innovatively propose the three-dimensional (3D) flower-like Bi 2 O 2 CO 3 /rGO composites for CAP electrochemical sensing. The best sensing parameters (pH, scan rate, accumulation conditions) were systematically investigated. As a result, the Bi 2 O 2 CO 3 /rGO/GCE sensor exhibits a peak current density of 381.91 µA/cm 2 , ultra-low detection limit (0.362 nM), and two wide linear ranges (0.001–10 μM, 10–100 μM), enabling both trace and high-concentration quantitative detection of CAP. These high sensing performances could be ascribed to the synergistic effect between rGO and Bi 2 O 2 CO 3 , which improves the stability of Bi 2 O 2 CO 3 /rGO composites. Their interfacial interaction accelerates electron transfer, lowers activation energy, and forms an efficient 3D electron/mass transport network. This sensor also applied in detecting CAP in lake water and milk samples with satisfied recovery rates. These findings underscore the Bi 2 O 2 CO 3 /rGO/GCE as a promising platform for sensitive CAP monitoring in environmental and food safety applications.