Electrochemical aptamer sensor based on bimetallic CuZr-MOF and AuNPs for ultrasensitive detection of organophosphorus pesticides in vegetables

To address the threats posed by organophosphorus pesticides (OPs) to human health and the environment, this study developed a highly sensitive electrochemical aptasensor based on gold nanoparticles (AuNPs) and a functionalized bimetallic copper-zirconium metal-organic framework (CuZr-MOF). In this system, Cu + doping greatly enhances electrical conductivity, after which Zr⁴⁺ provides excellent stability and a large specific surface area. The combination of AuNPs and CuZr-MOF formed a nanocomposite that enhanced sensitivity and enabled the stable immobilization of a thiol-modified broad-spectrum aptamer via Au-S bonding, facilitating efficient recognition of OPs. The aptasensor demonstrates exceptional performance across a concentration range of 1×10 -12 to 1×10 -6   M, with limits of detection of 2.36×10 -4 pM, 4.56×10 -2 pM, and 1.20×10 -2 pM for three representative OPs, and recovery rates ranging from 91.0% to 101.2%. The method’s reliability is further validated by liquid chromatography-tandem mass spectrometry (LC-MS/MS). This study presents a simple and effective approach for detecting OPs in vegetables, demonstrating significant potential for on-site food safety monitoring.