A colorimetric and fluorometric dual-functional chemodosimeter for highly sensitive and selective detection of Cu²⁺...

A new chemodosimeter, IN-P, an indolinium-naphthyl-picolinate conjugate, which incorporates the picolinate as the recognition group and the hemicyanine as the fluorophore, has been synthesized for the sensing of Cu²⁺ with a fluorescence "turn-on" response. The hydrolysis reaction-based sensing mechanism was systematically verified through ¹H NMR, HRMS, IR, and a DFT analysis. IN-P demonstrated outstanding performance characteristics, including excellent selectivity, high sensitivity (LOD of 13.6 nM), and a fast response time (within 5 min) for Cu²⁺ sensing. Additionally, it offers advantages such as simple synthesis, has good water-solubility, and can show dual colorimetric and fluorometric responses. Inspired by these favorable features, the IN-P has been applied for fluorescent imaging of Cu²⁺ in living cells and for the quantitative determination of Cu²⁺ in selected juice samples, with satisfactory results. Monitoring of Cu²⁺ ions, in different nutritional intakes, including fruit juice matrices, is essential since even trace levels of contamination can potentially lead to significant deleterious health effects, including several significant disabilities.