Histidine, Serine and Folic Acid-Functionalized And Boron and Iron-Doped Graphene Quantum Dot With Excellent Optical Behavior And Peroxidase-Like Activity For Colorimetric and Fluorescence Detection of H2o2 In Food

Abstract

Poor activity limits wide application of graphene quantum dot as nanozyme in biosensor, catalysis and biomedical. The paper report synthesis of histidine, serine and folic acid-functionalized and boron and iron-doped graphene quantum dot (Fe/B-GQD-HSF) by hydrothermal treatment. The as-synthesized Fe/B-GQD-HSF offers excellent fluorescence property and high peroxidase-like activity. Excitation of 330 nm ultraviolet light produces the maximum blue fluorescence and excitation of 480 nm visible light produces the maximum yellow fluorescence. The specific activity reaches 92.67 U g-1, which is better than that of all reported graphene quantum dots and the most metal-based nanozymes. Fe/B-GQD-HSF can catalyze oxidation of 3,3′,5,5′-tetramethylbenzidine with H2O2. Based on this, one dual-mode method was established for colorimetric and fluorescence detection of H2O2. The absorbance at 652 nm linearly increases with the increase of H2O2 concentration between 0.5 and 100 mM with detection limit of 0.43 mM. The fluorescence signal linearly decreases with the increase of H2O2 concentration between 0.05 and 100 mM with detection limit of 0.035 mM. The analytical method has been satisfactorily applied in detection of H2O2 in food. The study also paves one way for design and synthesis of functional graphene quantum dots with ideal fluorescence property and catalytic activity.

Keywords: Double-color fluorescence probe, Nanozyme, H2O2, Optical sensor