Crown daisy leaf waste–derived carbon dots: A simple and green fluorescent probe for copper ion

Abstract

In this paper, N‐doped carbon quantum dots (N‐CDs) were fabricated using crown daisy leaves, a kitchen waste, as carbon source. The synthesized N‐CDs possessed abundant surface functional groups, such as hydroxyl, carboxyl, and amino groups, and had good dispersibility in water. Because of the special fluorescence quenching property toward Cu2+, the synthesized N‐CDs can be exploited as an effective label‐free fluorescent probe for Cu2+ determination. The possible fluorescence sensing mechanism considered the selective coordination interaction between Cu2+ ion and the hydroxyl, carboxyl, and amino groups of the N‐CDs. The control experiments also showed that the N‐doped aromatic C–N heterocycle structure played a crucial role in selective sensing of Cu2+. The decrease in fluorescence efficiencies was linearly related with the Cu2+ concentrations in the range of 10.0nM to 120.0nM, with a response limit of 1.0nM. The prepared probe was also applied for Cu2+ determination in real river water.