Green chemistry approach for synthesis of copper nanoclusters from Cissus quadrangularis for fluorescence turn-off detection of imidacloprid pesticide

초록

Cissus quadrangularis belongs to the Vitaceae family, exhibiting diverse therapeutic applications, including aiding in weight loss, promoting bone healing, and combating worm infestations. In this work, blue-emitting copper nanoclusters (CuNCs) were prepared via a green chemistry approach using C. quadrangularis extract, abbreviated as CQ-CuNCs. The synthesized CQ-CuNCs displayed a strong emission peak at 430 nm when excited at 320 nm. The morphology of CQ-CuNCs was elucidated using field emission transmission electron microscopy (FE-TEM), showing a uniform core size of 2.18 nm, which is well correlated with the dynamic light scattering data (hydrodynamic diameter of CQ-CuNCs = 6.34 nm). The as-fabricated CQ-CuNCs acted as a chemosensor for fluorescence sensing of imidacloprid pesticide. The fluorescent CQ-CuNCs selectively sense imidacloprid pesticide with a remarkable fluorescence quenching, whereas no fluorescence quenching was induced by other pesticides and inorganic species. The sensitivity of the probe was assessed by measuring emission intensity as a function of various concentrations of imidacloprid (0.01–500 µM), showing the detection limit was 0.020 µM. In addition, the selective and sensitive ability of CQ-CuNCs was evaluated by quantifying imidacloprid pesticide in river water, agricultural soil, and cabbage samples, which enables the enviroanalytical applications of CQ-CuNCs. The CQ-CuNCs-based analytical strategy displays good recovery ranges from 98.29 to 99.86, with a relative standard deviation value < 2 for imidacloprid analysis, demonstrating the potential practical application of CQ-CuNCs for imidacloprid pesticide sensing in environmental and food samples.

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