Ultrasensitive Detection of Organophosphorus Pesticides Using Single-Molecule Conductance Measurement
Xuejun Dong, Ziyun Tang, Hua Zhang, Yong‐Jie Hu, Zhiyi Yao, Ruiyun Huang, Jie Bai, Yang Yang, Wenjing Hong
Abstract
Detection of organophosphorus pesticides (OPs) with high sensitivity in environmental samples is of vital importance for environmental safety and human health. However, it remains a challenge to achieve fM (10 –15 mol/L) sensitivity for detecting OPs. Herein, we developed an acetylcholinesterase sensor based on 3,3′,5,5′-tetramethylbenzidine (TMB) combining an enzyme-mediated strategy and scanning tunneling microscopy break junction (STM-BJ). Benefiting from the enzyme inhibition kinetics of OPs and the customized spectral clustering analysis method, our new strategy achieved the detection of methamidophos (MTMP) with a limit of 10 aM (10 –17 mol/L) and 3 times higher selectivity in mixed OPs. As applied to natural lake waters, it also exhibited high reproducibility, high stability, and good recovery. This work paves a new avenue toward the application of single-molecule conductance characterizations for biochemical analysis and environmental monitoring.