| In this thesis,heterogeneous sulfides with different structures（Cd S-Mo S2-1 and Cd S-Mo S2-2）were synthesized as materials for the modification of glassy carbon electrodes using the reaction of phosphomolybdic acid(PMo12)with cadmium nitrate（Cd（NO3）2）after different preparation schemes.The responses of Cd S-Mo S2-1 to lignocaine and Cd S-Mo S2-2to luteolin and quercetin were examined by cyclic voltammetry,differential pulse voltammetry,and AC impedance test,respectively,using an electrochemical sensor chemistry workstation three-electrode system.The results of both experiments showed good sensitivity,detection limits and electrochemical properties for the detectors.The real samples were tested and found to have good recoveries for the assayed samples.It is demonstrated that this paper successfully prepared electrochemical sensors with high sensitivity for rapid detection.The main content is briefly described as follows:1.The composite Cd S-Mo S2-1 was characterized by transmission electron microscopy,scanning electron microscopy and electrochemical analysis.Cd S-Mo S2-1 was used as an electrode material modified onto the surface of a glassy carbon electrode（GCE）as a working electrode,together with a reference electrode of silver/silver chloride（3 mol/L KCl）and a counter electrode of platinum wire,for the detection of luteolin.The results showed that the sample was detected in a buffer solution at the optimum p H（p H=4.0）without interference from other substances,and the electrode has a large specific surface area and can be used repeatedly.The linear ranges of the sensor for luteolin were 0.1 n M-2.28μM and 2.28μM-27.49μΜ,and the detection limit（S/N=3）was 0.018 n M.In order to verify whether the electrochemical sensor can be applied in real assays for real time fast detection applications,the content of Doklamini softgels was determined as the real test sample,and the sensor was found to have good recovery.2.The composite nanomaterial Cd S-Mo S2-2 was synthesized stepwise by hydrothermal method using crystals as precursors,and it was used as an electrode material to modify the surface of glassy carbon electrode（GCE）to construct an electrochemical sensor that can be used for the detection of quercetin and luteolin.The experimental results showed that the Cd S-Mo S2-2@GCE electrochemical sensor constructed with this material responded well to the two detectors.The detection limits（S/N=3）were 3.11 n M and 8.70 n M for luteolin at the optimum p H（p H=4.0）.p H（p H=4.0）buffer solution with significant anti-interference ability,and the recoveries were found to be within reasonable error limits for the real samples tested separately with good results.Based on the idea that differences in the composition ratio and morphology of composite materials can lead to different redox capabilities of electrochemical sensors for the detection of the materials to be measured,two heterogeneous heterogeneous sulfide nanomaterials were successfully designed and synthesized in this study to investigate the effects of their composition ratio and structural morphology on electrochemical studies.After experiments such as catalytic properties and impedance tests,the roles played by Cd S and Mo S2in the two composites can be found,and the former is found to play mainly a catalytic role and the latter an electron-conducting role.After scanning electron microscopy and transmission electron microscopy,it can be seen that both materials are composed of sheet-like stacking,but the nanotube structure of Cd S-Mo S2-2 is favorable to increase the contact area with the material to be measured and facilitate material transfer compared with the hexagonal structure of Cd S-Mo S2-1.EDS analysis shows that the percentage of Cd S in Cd S-Mo S2-1 is larger than that of Cd S-Mo S2-2,so the Cd S-Mo S2-1 composite has higher redox ability and high sensitivity to detect lower linear range,and the Cd S-Mo S2-2composite has higher percentage of Mo S2and possesses better conduction rate.The detection data of both materials were superior to those of previous sensors for the detection of quercetin and luteolin,confirming the successful synthesis of two heterogeneous sulfide nanomaterials and the preparation of highly specific and sensitive electrochemical sensors,which provide a fast and effective way to detect luteolin and quercetin,respectively.With the different surface morphology and substance content ratio of the modifier,it shows different effects on the selection of the detector and the size of the linear range,which can provide ideas for the selection of electrochemical electrode materials in the future. |
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