Broad-spectrum pesticide screening by multiple cholinesterases and thiocholine sensors assembled high-throughput optical array system

Abstract

Accurate screening of organophosphorus and carbamates pesticides from the complex real sample is crucial for water quality analysis and food safety control. Herein, a simple, low-cost and accurate pesticides screening method based on a high-throughput optical array system assembled by multiple cholinesterases (ChE) and thiocholine (TCh) sensors is described. The detection mechanism is that the inhibition of ChE activity by pesticides reduces the TCh produced by the hydrolysis of butyryl/acetylthiocholine iodide, thus changing the fluorescence intensity of TCh sensor. The diverse response of ChEs to pesticides and different affinity of sensors to TCh ensure the high-throughput and distinguishable signal output, which allow the establishment of high discrete pesticide database with intra-cluster agglomeration and inter-cluster dispersion. By using the database, the screening of unknown real contaminated samples were successfully operated, and the screened pesticide species and concentrations were consistent with high-performance liquid chromatography. This screening strategy demonstrates the feasibility of replacing existing complex mass spectrometry-based screening strategy with simple optical analysis, providing a new idea for the development of simple accurate screening technologies for widespread organic pollutants including pesticides.

Keywords: cholinesterase; fluorescent sensor array; linear discriminant analysis; pesticide residues; pesticide screening.