Solid-phase synthesized iron-mediated carbon dots nanozymes with fluorescence and peroxidase-like activity for multi-mode analysis of dopamine

Carbon dots (CDs) nanozymes open a new horizon for fabricating multi-mode analysis systems, but their practical applications are still limited by complicated synthesis strategy and single-function nature. Herein, a new type of iron and nitrogen co-doped carbon dots nanozyme was developed through simple pyrolyzing the solid mixture of ferrous bis-glycinate and ethylenediamine dihydrochloride. The Fe,N-CDs exhibit good optical properties that can emit obvious blue fluorescence and possess excellent peroxidase-like activity that can catalyze H 2 O 2 to generate reactive oxygen species. Based on the fluorescence and peroxidase-like activity of the Fe,N-CDs, a multi-mode detection platform for DA was constructed effectively, including naked eye colorimetric, UV–Vis ratiometric absorption, fluorescence quenching, and scanometric. The limit of detection can reach 10 nM, and the calibration curve was linear up to 30 μM. The multi-mode sensing system was successfully applied for the accurate determination of DA in various actual samples with a satisfactory recovery of 89.0–118.0 %.