A novel dual-signals peptide-based probe for highly selective detection of Cu(II) and glyphosate and its applications in smartphone-assisted test strips sensing system

Abstract

Glyphosate is widely used herbicides and causes several diseases in humans. Therefore, the detection of glyphosate is curial and urgent. Herein, a novel dual-signals probe L with colorimetric and fluorescent was designed and synthesized based on fluorescein isothiocyanate (FITC) labelled tetrapeptide backbone (Asp-Lys-Ser-His-NH2). L possessed good selectivity and high sensitivity to Cu2+ based on fluorescence “on–off” response and colorimetric visualization method, and the detection limit as low as 10.9 nM, forming the L-Cu2+ ensemble based on 1:1 stoichiometric ratio. Meanwhile, the L-Cu2+ ensemble had high selectivity, rapid response, low detection limit (11.3 nM) and naked eye recognition for detection of glyphosate. In addition, L-Cu2+ ensemble was succesfully used to detect glyphosate in actual water samples with the relative standard deviations (RSDs) lower than 3%, indicating that L-Cu2+ ensemble had potential application in the field of environmental detection. Moreover, test strips of L were prepared for rapid analysis of Cu2+ and glyphosate. Finally, smartphone-assisted test strips sensing system was constructed for semi-quantitative detection of glyphosate, which has the advantages of accurate, high specificity and strong anti-interference ability.