Abstract
The high-reliability simultaneous detection of trace heavy metal ions (HMIs) is of particular importance due to the fact that the synergistic toxicity arising from coexisting HMIs poses significant risks to human health. Conventional electrochemical detection utilizes the redox properties of HMIs itself for single-signal detection, with limitations in selectivity and accuracy. Herein, a ratiometric electrochemical aptasensor was developed to address these issues by integrating aptamers for indirect recognition and internal reference for signal calibration. Four detection strategies were systematically evaluated, with indirect ratiometric detection demonstrating superior anti-interference capability. Leveraging entropy-driven catalysis (EDC), the aptasensor achieved ultrasensitive simultaneous detection of Pb2+ and Hg2+ with detection limits of 0.2 and 0.1 ng mL-1. Practical validation using aquatic products was corresponded with ICP-MS. By addressing the challenges of selectivity/accuracy and combining the ultrasensitive advantages of EDC, a high-reliability and universal framework for multiple HMIs detection has been established to advance food safety applications.
