Abstract: Fe, N-doped carbon quantum dots (Fe-N-CDs) were synthesized via a one-step hydrothermal method using L-histidine (His) and ferrous sulfate heptahydrate (FeSO?·7H?O) as precursors. The introduction of Fe atoms may increase the number of active sites on the N-CDs surface and facilitate electron transfer during catalysis, thereby enhancing catalytic reaction rates and efficiency. The Fe-N-CDs exhibited significantly enhanced peroxidase-like activity. In the catalytic reaction, Fe-N-CDs decomposed H?O? to generate hydroxyl radicals (?OH), which oxidized colorless TMB (3,3',5,5'-tetramethylbenzidine) to blue oxidized TMB (oxTMB), producing a distinct UV-Vis absorption peak at 652 nm. Chlorogenic acid (CGA), known for its unique antioxidant properties, was introduced into this chromogenic system. The characteristic absorption peak of oxTMB disappeared, accompanied by gradual fading of the blue color. This phenomenon enables the detection of CGA in food samples. This study not only developed a carbon-based nanozyme with superior catalytic activity but also established a simple, rapid, and highly sensitive method for CGA detection.

Key words: Carbon dots, Naoeezymes, Chlorogenic acid, Colorimetric detection