%0 Journal Article
%T Coffee grounds-derived carbon quantum dots as peroxidase mimetics for colorimetric and fluorometric detection of ascorbic acid.
%A Zhu Y
%A Deng X
%A Chen J
%A Hu Z
%A Wu F
%J Food Chem
%V 429
%N 0
%D 2023 Dec 15
%M 37499505
%F 9.231
%R 10.1016/j.foodchem.2023.136957
%X In this study, we reported the eco-responsible synthesis of iron-doped carbon quantum dots (Fe-CQDs) from waste coffee grounds through a simple hydrothermal method. The Fe-CQDs exhibited high peroxidase-like activity, which could convert 3,3',5,5'-tetramethylbenzidine (TMB) into blue ox-TMB in the presence of H2O2. After adding ascorbic acid (AA) to above system, the blue solution faded. Based on this phenomenon, a colorimetric method for visual monitoring of H2O2 and AA was developed. Meanwhile, the fluorescence of Fe-CQDs can be quenched by the formed ox-TMB via inner filter effect (IFE), followed by the recovery upon the addition of AA. Therefore, Fe-CQDs can be acted as a fluorescent probe to detect H2O2 and AA through the "on-off-on" mode. Furthermore, the dual-recognition methods based on Fe-CQDs were used to measure AA content in beverage samples. Thus, this work would shed much light on converting waste into biomass CQDs and their potential applications in biomolecular detection.