Semi-quantitative and visual detection of Cu²⁺ and glyphosate in real samples and living cells using fluorescent and...

The excessive emission of copper ions (Cu²⁺) and the abuse of glyphosate (Glyp) have caused serious harm to the ecological environment and human health, so it is important to develop a fast and convenient method for the analysis of Cu²⁺ and glyphosate to ensure environmental and food safety. Herein, a dual-signals peptide-based probe (FASRH) with fluorescent and colorimetric was prepared using 5-carboxyl fluorescein modified tetrapeptide (Ala-Ser-Arg-His-NH₂). FASRH was successfully used to recognize Cu²⁺ as a fluorescence "on-off" probe, forming the FASRH-Cu²⁺ complex with non-fluorescence. As a new promising cascade probe, FASRH-Cu²⁺ complex probe has high selectivity (only Glyp), good sensitivity (50.2 nM), good anti-interference ability and wide pH range (7.0-11.0) for the detection of glyphosate by ligand replacement method. In addition, the recognizable color changed markedly under 365 nm UV light and natural light. Notably, FASRH not only achieved accurate monitoring of Cu²⁺ and glyphosate in two real water samples, but also successfully applied to detect Cu²⁺ and glyphosate in live Hacat cells based on low cytotoxicity. Moreover, it is worth noting that FASRH-impregnated test strips exhibited significant fluorescence and colorimetric color changes for Cu²⁺ and glyphosate via naked eye. Furthermore, smartphone-assisted FASRH was used for the portable detection of Cu²⁺ and glyphosate based on the advantages of simplicity, low cost and fast response.