Polymerizing dopamine onto Q-graphene scaffolds towards the fluorescent nanocomposites with high aqueous stability and enhanced fluorescence for the fluorescence analysis and imaging of copper ions

Dopamine (DA) was polymerized onto the scaffolds of Q-graphene (QG) nanomaterials by the one-pot H2O2 oxidation under the microwave radiations. The so yielded fluorescent QG@PDA nanocomposites could present the high aqueous stability and photostability. Unexpectedly, they could display the enhanced fluorescence and photoluminescence, which are about 1.5-time larger than those of the fluorescent PDA nanoparticles. More importantly, the fluorescence and photoluminescence of QG@PDA nanocomposites could be specifically quenched by Cu2+ ions, which could be efficiently restored by using the Cu2+-chelating ligand (i.e., EDTA). The developed fluorimetry was applied to detect Cu2+ ions in wastewater with the detection limit down to about 10 nM. The feasibility of the quantitative observations by the fluorescence imaging for Cu2+ ions could also be expected. This QG@PDA-based fluorimetry for Cu2+ ions is rapid, sensitive, selective, and field-applicable, promising the potential applications in the environmental and industrial fields.