Synthesis of carbon dots from corn stover and their application in quercetin detection

In this work, carbon dots with green fluorescence were prepared by one-step hydrothermal reaction using corn stover as a carbon source. The carbon dots prepared under the optimal synthesis conditions had a spherical morphology with an average particle size of 2.07 ± 0.48 nm, and their fluorescence quantum yield reached 37.4%. The effects of various metal ions and organic small molecules on the fluorescence intensity of carbon dots were tested. The results showed that only quercetin caused a strong fluorescence quench of carbon dots, which were constructed as highly selective quercetin fluorescent probes based on the inner filter effect and the static quenching effect. The carbon dots quenched by quercetin exhibited high sensitivity for a fluorescence quench process, the quercetin concentration and the difference in fluorescence intensity of carbon dots (F0/F) showed linear relationship between two variables. For low the quercetin concentration was 10 ∼ 100 µmol·L−1, the standard curve was F0/F = 0.0078X + 1.08 (R2=0.9943); while the quercetin concentration was 100 ∼ 200 µmol·L−1, the standard curve was F0/F = 0.015X + 0.341 (R2=0.9937), and its limit of detection was 6.41 µmol·L−1.