Construction of Chitosan-Modified Naphthalimide Fluorescence Probe for Selective Detection of Cu²

A chitosan-based Cu²⁺ fluorescent probe was designed and synthesized independently using the C-2-amino group of chitosan with 1, 8-naphthalimide derivatives. A series of experiments were conducted to characterize the optical properties of the grafted probe. The fluorescence quenching effect was investigated based on the interactions between the probe and common metals. It was found that the proposed probe displayed selective interaction with Cu²⁺ over other metal ions and anions, reaching equilibrium within 5 min.