Application Research Of Chemical Sensor Based On Carbon Composites

Carbon composites with excellent physical and chemical properties and is widely applied to various fields. Among them, the chemical sensors based on carbon composites played an important role in the aspects of environmental pollutants and detection of tumor markers. However, in terms of environmental pollution detection, the chemical sensors based on carbon composites on the determination of environmental pollutants that have no electrochemical activity are still remain large gaps. For the detection of tumor markers is more for basic research, design and synthesis of high performance carbon composites for chemical sensors used in the detection of tumor markers still is a research hotspot in the field of chemical sensing. This article focused on using the excellent properties of carbon composites to build new type of chemical sensors, and applied to determination of environmental pollutants and tumor markers. The main research contents of this paper are as follows:1. Using the potentiostatic polymerization method to immobilization the water-soluble ?-cyclodextrin polymer functionalization graphene onto the pyrolytic graphite electrode surface with polypyrrole as conductive polymers. Ferrocene can form a host-guest complex with ?-cyclodextrin polymer, when addition of the polychlorinated biphenyl in the solution containing the probe ferrocene, the polychlorinated biphenyl will replace the ferrocene in the cavity due to polychlorinated biphenyls has higher affinity towards ?-cyclodextrin polymer than ferrocene and in result both the oxidation and reduction peaks of ferrocene decrease. The determination of polychlorinated biphenyl according to the change of the peak current of ferrocene was established in this paper. The result indicated that the detection range of this method is 1.0×10-12¹.0×10-5 mo L/L and the detection limit is 5.0×10^-13 mo L/L. Compared with other detection methods reported in literatures, the sensor has better performance.2. The 2,6-diaminoanthraquinone as an electrochemical probe and through acyl chloride reaction synthesis of 2,6-diaminoanthraquinone functionalized grapheme. Then the electrochemical sensor was developed based on 2,6-diaminoanthraquinone functionalized grapheme doped poly?3,4-ethylenedioxythiophene? composite film modified glassy carbon electrode. The high sensitive electrochemical detection method was established based on the strong ?-? interaction between polycyclic aromatic hydrocarbons and 2,6-diaminoanthraquinone. The result indicated that the detection range of this method is 1.0×10-12¹.0×10-7 mol/L and the detection limit is 1.0×10^-13 mol/L. The sensor was used for measurement of practical sample analysis, the result has good consistency with HPLC methods. The method has a profound impact on the design of a convenient platform for rapid screening and determination of PAHs in environment.3. The gold nanoparticle/PDDA/graphene composites were synthesized as as fixed antibody matrix and applied onto the surface of the glassy carbon electrode. With [Fe?CN?6]3-/4- as the probe, using differential pulse voltammetry explores the different concentration carcinoembryonic antigen on the influence of electrode electrochemical signals based on the bio-recognition reactions of antigen-antibody. The results showed that the peak current of the probe decreases gradually with an increase in the concentrations of carcinoembryonic antigen. The peak current change was found to be proportional to the logarithm of carcinoembryonic antigen concentration in range from 1.0×10-10 to 1.0×10-5 g/m L. The detection limit evaluated to be 5.0×10^-11 g/m L for carcinoembryonic antigen. In addition, the results of spiked tests showed acceptable recovery rate.4. The Au nanoclusters as antibody capture base were modified onto the glassy carbon electrode surface by using cyclic voltammetry. Au NPs@PAMAM-C₆₀ composite was synthesized as tracing tag to label detection antibodies?Ab2?, with a sandwich-type immunoreaction, the Au NPs@PAMAM-C₆₀ labeled Ab2 was captured on the surface of an immunosensor to further induce a silver deposition process. The electrochemical stripping signal of the deposited silver nanoparticles in KCl was used to monitor the immunoreaction. The influence of different concentrations of alpha fetoprotein on the stripping signal of the deposited silver nanoparticles was studied and the result indicated that the peak current increases linear with an increase in the concentrations of alpha fetoprotein in the range from 0.001 to 10 ng/m L and the detection limit is 0.0001 ng/m L. Compared with other methods reported in literatures, the sensitivity had significantly improved.5. The Au nanoclusters as antibody capture base were modified onto the glassy carbon electrode surface by using cyclic voltammetry. Au NPs@L-cys-C₆₀ composite was synthesized as the redox nanoprobe and nanocarrier to label detection antibodies?Ab2?, with a sandwich-type immunoreaction, the Au NPs@L-cys-C₆₀ labeled Ab2 was captured on the surface of an immunosensor. The influence of different concentration of carcinoembryonic antigen on the peak current of the nanoprobe was explored and the results showed that the peak current of the nanoprobe increases gradually with an increase in the concentrations of carcinoembryonic antigen. In the range of 0.001¹0 ng/m L, peak current changes linearly with the increasing of the logarithm of carcinoembryonic antigen concentration and the detection limit evaluated to be 0.0005 ng/m L. At the same time, the experimental results show that the sensor has good stability, reproducibility and specificity.