Aptamer Recognition-Driven Homogeneous Electrochemical Strategy for Simultaneous Analysis of Multiple Pesticides without Interference of Color and Fluorescence.

Credible and simultaneous determination of multiple pesticides is highly desirable for guaranteeing food safety. However, the current methods are limited to significant interference of color and fluorescence or electrode's modification and mainly focus on the analysis of a single pesticide. Herein, we proposed a novel aptamer-based homogeneous electrochemical system for highly sensitive and simultaneous analysis of multiple pesticides based on target pesticide-switched exonuclease III (Exo III)-assisted signal amplification. The recognition of hairpin probes by target pesticides impels the production of pesticide-DNA complexes, which hybridize with electroactive dye-labeled DNA to form double-stranded DNA, subsequently initiating an Exo III-assisted digestion reaction to generate abundant electroactive dye-tagged mononucleotides. In comparison with pesticide deficiency, two higher differential pulse voltammetry (DPV) currents are measured, which rely on the amount of target pesticides. Therefore, simultaneous analysis of two pesticides is realized with limits of detection of 0.0048 and 0.0089 nM, respectively, comparable or superior to those of known methods that focused on a single pesticide. Moreover, the proposed system is successfully employed to simultaneously evaluate the residual level of acetamiprid and profenofos in Brassica chinensis and thus will find more useful applications for pesticide-related food safety.