| As an important intermediate biosubstance in the biochemical process, hydrogen peroxide(H2O2) is conducive to regulate physiological processes such as immune cell activation, but its high concentration will produce too much active oxygen free radicals which would cause harmful behaviors to organisms such as cells to become cancerous, so it is of great significance for biomedical by rapid and sensitive detection of H2O2. Although natural peroxidases have high catalytic efficiency and specificity for detecting H2O2, but their poor stability, harsh reaction conditions and other defects would limit the development of its own, which encourage people pay attention to synthesize mimetic peroxidase to replace natural peroxidase. With the development of nanotechnology, the research of nanomaterials in mimicing peroxidase have attracted widespread attention. Among various nanomaterials, carbon-based materials and noble metal nanomaterials with their composites are becoming the hot spot of research.Based on properties of mimetic peroxidase of nitrogen doped porous carbon(pCxN1-x) and platinum-based nanoparticles(Pt-BNPs), this paper has constructed new systems of mimetic peroxidase and studied activities of pCxN1-x with its platinum based nanocomposites(Pt-pCxN1-x) mimetic peroxidase. This paper also has discussed the process of catalytic kinetic and completed the detection of H2O2. The main research contents of the paper are the following three aspects:1. The hard template method was adopted to make holes for melamine formaldehyde resin with nano calcium carbonate, so pCxN1-x was synthesized, and using electron microscope, X-ray diffraction, N2 adsorption/desorption, thermogravimetric with other methods to characterize the morphology and structure. By using o-phenylendiamine chromogenic system, it was found that pCxN1-x possesss the activity of mimetic peroxidase. By discussing factors such as pH, temperature, substrate concentrations on its catalytic activity, it was found the optimum pH was 3.0, the optimal temperature for 55 °C, and the optimum concentration for o-phenylendiamine and hydrogen peroxide were 800 μmol/L and 50 mmol/L, respectively. Morever, the catalytic process of pCxN1-x was accord with mie equation, and its michaelis constant Km and maximum reaction rate Vmax had been determined. The linear range for detecting H2O2 by pCx N1-x was from 0.01 mmol/L to 0.1 mmol/L and the detection limit was 0.0035 mmol/L.2. With the method of microwave assisted heating, Pt-pCxN1- x nanocomposites was synthesised in situ, and its morphology and structure were characterizatied by TEM, SEM-EDS mapping, X-ray photoelectron spectroscopy, N2 adsorption/desorption, Raman spectroscopy and so on. Through the chromogenic system of 3, 3‘, 5, 5‘- tetramethyl benzidine and H2O2, Pt-pCxN1-x nanocomposites exhibited the activity of mimetic peroxidase. By studying its catalytic kinetics and michaelis constant, Pt-pCxN1-x had exhibited the enhanced activity of mimetic peroxidase compared to its single component.3. Based on the activity of mimetic peroxidase of Pt-pCxN1-x nanocomposite, an no-enzyme electrochemical sensor was constructed with Pt-pCxN1-x as electrode materials. The linear range for detecting H2O2 by Pt-pCxN1-x was from 0.025 mmol/L to 5.725 mmol/L and the detection limit was 2.29 μmol/L. Using standard addition recovery method to determinate H2O2 in disinfection of fetal bovine serum, it was found that the standard addition recovery rate of all samples was from 99.65 % to 102.07 %, and the relative standard deviations were less than 3.0 %. |
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