Construction Of Electrochemical And Fluorescence Sensing System Based On Supramolecular Host And Its Application In Pesticide And Drug Molecule Detection

The fluorescent sensors and electrochemical sensors have great advantages, such as simple operation, low cost, easy miniaturization of equipment, and in situ detection,compared with traditional high performance liquid chromatography, gas phase analysis compare,. Furthermore, fluorescent sensors and electrochemical sensors also have some advantages, such as fast detection, rapid, sensitive and selective, and it becomes an important tool for trace detection of various fields of detection and analysis. In this work, through the use of β-cyclodextrin(β-CD) and p-sulfonated calix[6]arene(SCX6) supramolecular recognition, and graphene nanomaterials fluorescence quenching properties and adsorption and high conductivity, supramolecular and graphene nanocomposites has been prepared. And this work conduct the sensors of dimethomorph and medicine of tadalafil and labetalol hydrochloride by used the nanocomposites. The main research contents of this paper are as follows:(1) SS-β-CD-RGO nanocomposites were prepared by a wet-chemical route. Dimethomorph and disulfide linked β-cyclodextrin(SS-β-CD) inclusion pattern is determined by 2D NMR spectroscopy. A fluorescence method towards dimethomorph detection was developed based on competitive host-guest interaction by selecting safranine T (ST) and (SS-P-CD) functionalized graphene (SS-β-CD-RGO) as the "reporter pair". The mechanism of the competitive host-guest interaction was clarified by molecular docking. The fluorescence analysis of the linear range of the sensor was 0.50-20.0μM and 20.0-32.0μM, the proposed detection method for dimethomorph showed a detection limit of 0.135μM.(2) This chapter described the comparison of (β-CD) and p-sulfonated calix[6]arene (SCX6) functionalized reduced graphene oxide (RGO) for recognition of tadalafil. Tadalafil and two macrocycles (β-CD and SCX6) were selected as the guest and host molecules, respectively. The β-CD@RGO and SCX6@RGO composites were prepared by a wet-chemical route. The SCX6@RGO showed a higher electrochemical response than β-CD@RGO, which was caused by the higher recognition capability of SCX6 than β-CD. By combining the merits of SCX6 and the RGO, a sensitive electrochemical sensing platform was developed based on the SCX6@RGO nanohybrids. A linear response range of 0.1 to 50.0μM and 50.0 to 1000.0μM for tadalafil with a low detection limit of 0.045μM was obtained by using this method.(3) This chapter prepared a nanocomposites of graphene(RGO), manganese dioxide(MnO2) and p-sulfonated calix[6]arene(SCX6) by a simple wet-chemical route. Graphene, manganese dioxide and p-sulfonated calix[6]arene has the the characteristics of fluorescence quenching, and p-sulfonated calix[6]arene also has supramolecular recognition of hydrochloride labetalol. The inclusion pattern of labetalol and SCX6 is clarified by 2D NMR and. A fluorescence method towards labetalol detection has been developed based on competitive host-guest interaction by selecting rhodamine 6G (R6G), MnO2 and p-sulfonated calix[6]arene (SCX6) functionalized graphene (MnO2@RGO-SCX6). The linear range of this method is 1.0 to 12.0μM, and the method also have an low detection limit of 0.25μM.The results of this study provide new methods for rapid detection of pesticides and drug molecules.