Cu2+ assisted carnation-like fluorescent metal–organic framework for triple-mode detection of glyphosate in food samples

Herein, by employing a novel synthesized ligand H2L, a flower-like luminescent metal-organic framework IRMOF-3-L was constructed for developing a triple-mode sensor for glyphosate (Glyp) detection. The ligand H2L was designed to contain three functional parts, which endowed the resulted IRMOF-3-L with peroxidase-like activity and unique fluorescence property, as well as specific combining capacity for Cu2+ to quench its fluorescence. The quenched fluorescence of IRMOF-3-L/Cu2+ could be recovered by Glyp to realize fluorescence detection of Glyp. Besides, the peroxidase activity of IRMOF-3-L/Cu2+ could also be inhibited by Glyp, and result in the decrease of catalysate oxTMB, concurrently reducing the changes of colorimetric and SERS signal. Therefore, the fluorescent/colorimetric/SERS triple-mode based detection of Glyp was favorably realized, and the detection limits were calculated as low as 0.738, 2.26 and 0.186 nM, respectively. Furthermore, a portable test strips-smartphone sensing platform was constructed for point of care testing of Glyp in food samples.