Fabrication of highly fluorescent graphene quantum dots for quantification of As 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 As 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 As via aggregation-based fluorescence "turn-off" mechanism. The linear range for quantitating As 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 As ion in water samples. The CA-GQDs-embedded paper strip can be easily extended for assaying of As ion, which meets the demand for monitoring of As ion in real samples.