A dual pyridinium-tetraarylimidazole fluorescent sensor for detection of the herbicide quizalofop-p-ethyl

Abstract

Quizalofop-p-ethyl is a highly effective herbicide but threatens both human health and environmental safety when improper use. Therefore, the simple and in-situ method on detecting quizalofop-p-ethyl is extremely expected. In this work, we designed and synthesized a dual pyridinium-tetraarylimidazole (DPT) via a simple and straightforward synthetic route. Upon binding quizalofop-p-ethyl, DPT exhibits a turn-on blue-green fluorescence response. High selectivity was demonstrated across 28 different herbicides and ions. The probe shows good linearity over a quizalofop-p-ethyl concentration range of 0-0.1 equiv., with a limitation of detection of 1.05 × 10 -7 M. Mechanistic studies indicate that the turn-on fluorescence could be attributed to the strong molecular interaction based on hydrogen bonding, electrostatic interaction, π-π stacking and hydrophobic interaction between host and guest. The sensing capability of DPT has been successfully validated in test-strip assays, soil detection, plastic film and simulated water samples, demonstrating that this sensor enables simple, rapid, and on-site detection of quizalofop-p-ethyl in complex environments.