Construction Of Electrochemical Sensor Based On Novel Carbon Nano-composite Materials And Its Application Analysis

This thesis is aim to design some highly sensitive and selective electrochemical sensors. Which were applied to study electrochemical behavior of bisphenol series in environmental hormone, and then established a method for the detection of biological samples and environmental water samples. The main research contents are described as follows:Part 1:In this work, a new platinum (Pt) nanoparticle-functionalized poly (diallyl dimethyl ammonium chloride) (PDDA)-diamond powder (DMP) composite-modified glassy carbon electrode (GCE) was fabricated for electrochemical sensing by thermal reduction method and self assembly method. Pt/PDDA-DMP/GCE was used for simultaneous determination of bisphenol A (BPA) and bisphenol S (BPS) in 0.1 M phosphate buffer solution (PBS pH=6.0). The simultaneous determination of BPA and BPS by cyclic voltammetry yielded a difference of 0.316 V, which was sufficiently large for their potential recognition and simultaneous detection in mixtures. The experimental results showed that the oxidation of BPA and BPS on Pt/PDDA-DM/GCE was a completely irreversible adsorption-controlled process, and the transfer numbers of electronic and proton was equaled. Differential pulse voltammetry was successfully used to simultaneously quantify BPA and BPS within the concentration range of 5.0-30.0?M and 10.0-60.0?M under optimal conditions, respectively. The detection limits (S/N=3) of Pt/PDDA- DMP/GCE for BPA and BPS were 0.6 ?M and 2.0 ?M, respectively. The proposed method was successfully applied to determine BPA and BPS in biological samples.Part 2:A novel composite Gr-CNTs were prepared by hydrothermal synthesis method, then the protonated melamine (MAM) was loaded on it, the hybrid denoted as MAM/Gr-CNTs. This was used to modify GCE denoted as MAM/Gr-CNTs/GCE, use it sensitive determination of BPA and BPF. The electrochemical behaviors of BPA and BPF on MAM/Gr-CNTs/GCE were investigated by CV method. The electrochemical experimental results showed that the MAM/Gr-CNTs modified GCE exhibited excellent electrocatalytic activity to BPA and BPF. DPV method was used to investigate the relationship between oxidation peak current and the concentration of BPA and BPF, the result showed that with their concentration increased the corresponding oxidation peak current also increasing. The oxidation peak current and the concentration performance good linear relationship of BPA and BPF, the range of BPA was 5.57-27.0 ?M and 40.1-85.8?M, and the range of BPF was 52.9-102.0?M. Besides, this work also researched the electrochemical kinetic parameters of BPA and BPF, the results showed that the electron transfer number of BPA and BPF was equaled with the number of proton, the number of BPA and BPF was 2 and 4 respectively, and they all belong to the first order reaction. The modified electrode was used to analysis determination of BPA and BPF in 5 kinds of water samples and achieved satisfactory results.