| Hydrogen peroxide (H2O2) is a small molecule compound, it is also very common in nature. But due to the great importance of H2O2 in biological systems and its practical applications, the development of efficient electrochemical H2O2 sensors has a special attraction for researchers. Various materials have been applied to the construction of H2O2 sensors. In this article, some novel nanocomposites have been synthesized and modified on the surface of electrodes to construct non-enzyme electrochemical sensor and realize the effective determination of hydrogen peroxide. This work mainly concentrated in the following respects:1. Fe3O4 magnetic nanoparticles (Fe3O4MNPs), grapheme oxide (GO) and polyamidoamine dendrimer (PAMAM-G4) were applied to construct electrochemical H2O2 sensors. Firstly, nanocomposites were prepared and modified on the surface of gold electrode as the work electrode. Fe3O4MNPs possess enzyme mimetic activity and good biocompatibility, graphene oxide (GO) possesses a lot of oxygen-contained functional groups, and multifunctional iron oxide nanoparticle-attached graphene nanosheets can show excellent comprehensive performance. PAMAM possesses a high density of surface active groups, good structural homogeneity. It also constructs layer-by-layer assembly films with other species under the action of electrostatic interactions. The detection of H2O2 was studied by the method of Amperometric i-t Curve among the outstanding performance of the composites. Under the optimized experimental conditions, H2O2 could be detected in a linear calibration range of 2.0× 10-5～1.0×10-3 mol·L-1 with a correlation coefficient of 0.9950 (n=10), the detection limit was 2.0×10-6 mol·L-1 (3σ) and the recovery ratio was 96.9%～108.1%, which indicated that the accuracy of this method is excellent. The modified electrodes display excellent electrochemical performance, good reproducibility, and long-term stability.2. The polythiophene-graphene oxide compound membrane and Prussian blue film were deposited sequentially on the surface of glassy carbon electrode by cyclic voltammetry. Due to its excellent electrocatalysis and its analogy with peroxidase enzymes, PB has been widely used in the amperometric biosensors. Meanwhile, the poly thiophene-graphene oxide compound membrane exhibited a good electrochemical stability. Under the combined effect of both, the detection of H2O2 was studied by the method of Amperometric i-t Curve. Its linear calibration range of 1.0×10-6～1.0× 10-4 mol·L-1 and its detection limits as low as 3.2×10-7 mol·L-1 (3σ). It shows polymer membrane is stable, easy to store. The sensor has potential application for the detection of H2O2.3. Nitrogen-doped graphene was synthesized by a hydrothermal method including graphene oxide and carbamide as the raw materials, which mixed in a certain proportion. Meanwhile, gold nanopaticules were applied in electrochemical sensor, possessing unique electron and electrochemical properties. Then both of them were modified on the surface of the glassy carbon electrode to detect H2O2. Lots of oxygen-contained functional groups were separated from GO because of the addition of carbamide, generating the rich network porous structure and enhancing capacitive performance of materials. Under the optimum conditions, H2O2 was detected by differential pulse voltammetry (DPV). It shows a good linear relationship with the concentration of H2O2 from 1.0×10-7 mol·L-1 to 1.0×10-5 mol·L-1. Its detection limits was 4.9×10-8 mol·L-1 (3σ). This sensor is simple, reproducible, indicating nitrogen-doped graphene oxide in the field of electrochemical sensors have great prospects. |
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