A novel colorimetric and fluorescent sensor for the highly specific detection of Cu2+ and glyphosate based on a quinolimide-Schiff base

Abstract

As common pollutants, Cu2+ and glyphosate (Gly) pose a serious threat to the environment and human health. There is an urgent need to develop tools for monitoring Cu2+ and Gly. Herein, a novel quinolimide-Schiff base, 2-(pyridin-3-yl)-5-butyl-9-(2-((2-hydroxybenzylidene)amino)ethylamino)-4,6-quinolimide (BDSYQ), was prepared for specifically detecting Cu2+ and Gly through colorimetric and fluorescent dual-modes. After binding Cu2+, BDSYQ exhibited the changed color from chartreuse to orange-brown and quenched fluorescence with the detection limit (LOD) of 66.8 nM. Job's plots, high-resolution mass spectrometry (HRMS), and theoretical calculations revealed the 1:1 stoichiometry of BDSYQ with Cu2+. Subsequently, the BDSYQ-Cu2+ complex had the excellent selectivity, convenient visualization, good anti-interference ability, low LOD (73.3 nM), and short response time (within 60 s) for sensing Gly through the competitive coordination. Meanwhile, test strips contained BDSYQ were successfully utilized for visually detecting Cu2+ and Gly in daylight and 365 nm ultraviolet light. And high selectivities of BDSYQ for Cu2+ and Gly were also clearly observed by fluorescence RGB analysis. Notably, BDSYQ had accurately monitored Cu2+ and Gly in real water and agricultural product samples, and had successfully imaged Cu2+ and Gly in living cells.