A pyrene-based ratiometric probe for nanomolar level detection of glyphosate in food and environmental samples and its application for live-cell imaging

A reversible chromogenic probe based on a pyrene-linked bispicolyl amphiphile has been utilized for ratiometric, nanomolar level (LOD: 1.3 nM) detection of glyphosate in Brij-58 micelle medium. The probe shows a change in solution color from greenish-yellow to colorless with Cu2+ ions along with fluorescence quenching. When the solution was subsequently exposed to glyphosate, a ratiometric color-change from colorless to greenish-yellow was noticed, in addition to a turn-on fluorescence (green) response. Mechanistic investigations indicate dissociation of the preformed metal complex (1.Cu2+) in the presence of glyphosate, which triggers the release of unbound probe in the reaction medium. When 1.Hg2+ was used as the recognition template instead of 1.Cu2+, no interaction was observed with glyphosate. Considering its high sensitivity, 1.Cu2+ was further utilized for screening of real-life samples, such as water, soil, crops and packaged food items. Finally, the present sensory system is utilized for fluorescence bioimaging of intracellular glyphosate.

Automated summary

A reversible chromogenic probe based on a pyrene-linked bispicolyl amphiphile has been developed for nanomolar level detection of glyphosate in Brij-58 micelle medium, showing color and fluorescence changes with Cu2+ ions and glyphosate.