A Novel Dual-Working-Electrode Adaptive-Compensation and Dual-Signal-Amplification Sensor for High-Precision and High-Sensitivity Detection of Pb2+ in Random Environments

Abstract

To achieve high-precision and high-sensitivity detection of Pb²⁺ in random environments, a novel dual working electrode adaptive compensation and dual signal amplification sensor has been proposed. In a randomly fluctuating environment, one working electrode was modified with the target recognition element and thus generates both signal and noise, whereas the other electrode lacks the target modification and responds only to background noise. Two electrode signals were subtracted to eliminate background noise and achieve adaptive compensation. The imprinted sensor was prepared using chitosan as the functional monomer, followed by immobilization of specific DNA enzymes (DNAzyme) on its surface to construct a DNAzyme-imprinted dual-signal amplification sensor. The target Pb²⁺ interacted with the imprinting site and DNAzyme respectively, generating a dual signal amplification effect. The feasibility and adaptive compensation performance of the DNAzyme-imprinted sensor were analyzed, and the elementary reaction steps of the electrochemical process were investigated through kinetic analysis. The results indicate that the proposed method has a detection range of 10–80 nmol/L and a detection limit (LOD) of 5.52 nmol/L (3σ/slope). Within the temperature range of 20–36 °C, the detection error significantly decreased to 7.03%. The detection error significantly decreased to 6.21% within the pH range of 6.65–7.28, confirming the high sensitivity and adaptive compensation capability of this method. It has a high recovery rate in real water experiments, providing a high-precision and highly sensitive new method for detecting heavy metal ions in random water environments.