An efficient fluorescence sensor based on chitosan-modified graphitic carbon nitride for selective determination of Cu2+ ions

An effective, feasible and novel fluorescence sensor based on modified graphitic carbon nitride (g-C3N4) was constructed for the detection of Cu2+ ions. Carbon nitride nanosheets were obtained by liquid exfoliation in an acid solution and then modified by chitosan with an abundance of active sites. The as-prepared material was characterized by various methods including SEM, FT-IR, XRD, Raman, UV–vis and XPS. The modification material emitted enhanced fluorescence at 433 nm under the excitation of 368 nm and exhibited fluorescence quenching behaviors in the presence of Cu2+. The fluorescence intensity decrement was proportional to the concentration of Cu2+ ions ranging from 0 to 4.0 μM and 4.0 to 50.0 μM with a detection limit as low as 9 nM under optimal conditions. As a result of the improved sensing performance, the as-prepared g-C3N4-based material presented strong affinity, sensitivity, specificity and stability for metal ions and had a promising application for fluorescence detection.