Electrochemical aptasensor based on Zr-MOF@Ag nanocomposite for the rapid detection of chloramphenicol in honey, milk and lake water

Despite global regulatory bans due to its hematotoxic effects, chloramphenicol (CAP) persists as an illicit veterinary antibiotic in food animals owing to its low cost and broad-spectrum efficacy. Current analytical methods to monitor CAP residues in animal-derived foods face critical limitations: instrumental analyses rely on expensive equipment and specialized operations, while immunoassays lack sufficient sensitivity for regulatory compliance. Here, we develop an ultrasensitive electrochemical aptasensor leveraging a zirconium MOF‑silver nanocomposite (Zr-MOF@Ag), which effectively enhances charge transfer and facilitates aptamer immobilization. Under optimized detection conditions, the electrochemical aptasensor yielded a wide linear range of 1–100 ng/mL (r 2  = 0.990) with an ultralow limit of detection (LOD) of 9.94 pg/mL. Additionally, the sensor showed no cross-reactivity with other veterinary drugs, with RSD of 1.00–0.94 % for intra- and inter-batch repeatability, respectively. The recovery rates of spiked samples ranged from 95.1 to 108.4 %.