Fabrication of highly fluorescent graphene quantum dots for quantification of As³⁺ ion using modified cellulose paper

Easy, economical, and swift detecting tools are very demanded for assaying various chemical species. The introduction of label-free paper-based read-out devices has significantly reached the demand of analytical science for target analytes assays. Herein, a facile, and disposable inexpensive paper-based sensing tool was fabricated for sensing As³⁺ ion using graphene quantum dots (GQDs) as a fluorescent reader. The CA-GQDs were synthesized using citric acid (CA) as a precursor via the pyrolysis method, further physisorbed on the cellulose substrate for sensing of As³⁺ via aggregation-based fluorescence "turn-off" mechanism. The linear range for quantitating As³⁺ ion is in the range of 0.05-50 μM with a detection limit of 10 nM. The practical application of the CA-GQDs-based analytical platform was verified by assaying As³⁺ ion in water samples. The CA-GQDs-embedded paper strip can be easily extended for assaying of As³⁺ ion, which meets the demand for monitoring of As³⁺ ion in real samples.