Use of Carbon Dots Synthesized from Citrate as a Fluorescent Probe for Quercetin Determination in Tea and Beer Samples

In this work, carbon dots (CDs) prepared by a one-step hydrothermal method were employed for the determination of quercetin in teas and beers. The fluorescence quenching of CDs was proportional to the concentration of quercetin. Under optimum experimental conditions, linear quenching was observed for quercetin in the range of 1.0 to 10 mg L-1 (F/F0 = (0.1511 ± 0.0075)[Q] + (0.8922 ± 0.0384), R2 = 0.9926), at room temperature, using 80 μL CDs and 0.1 mol L-1 Na2HPO4/NaOH buffer solution (pH 11.0). A limit of detection (3σ criterion) of 0.85 mg L-1, and a relative standard deviation of 0.21%...