Study On The Application At Tungsten Based Material Modiifed Carbon Paste Electrode

As a chemical compound of transient metals, nano-WO₃not only has thecharacteristics of reversible electrochromism and catalytic properties, but also hasacute sensitivity to such gases as NO_x, O₃, O₂, H₂S, NH3, which can be widelyapplied to pharmaceutical industry, process control, environmental monitoring, etc.But little attention has been paid to its use as a kind of electrode material. The presentthesis conducts a series of research on the use of tungsten based material modifiedcarbon paste electrode, which is generated from WCl6as the main raw material byusing solvothermal method, lasting for16hours at the temperature of180℃. Themain aspects are as follows:1. WO₃nanowire, synthesized using a simple hydrothermal technique, was usedto modify the carbon paste electrode （CPE）. Determination of eugenol wasinvestigated under the methods of cyclic voltammetry and differentiation pulsevoltammetry. Therefore, optimal conditions have been discovered, on the basis ofwhich the linear equation for the determination of eugenol content has beenestablished and evaluation has been made on the reproducibility and recovery rate ofthe electrode.2. Nano-MnWO₄was obtained by mixing a certain amount of MnCl2in thepreparation process of WO₃. Nano-MnWO₄was successfully modified the carbonpaste electrode.It shows that nano-MnWO₄modified carbon paste electrode canimprove the electrochemical properties of pure WO₃modified carbon paste electrode,the accumulation time of the determination of eugenol reduced to60seconds. It isalso displayed that the linear range moves towards the area of lower concentration andeven as low as8×10-9mol/L, which brings better linearity and reproducibility.Assessment recovery is also carried out.3. The determination of honokiol is carried out under the methods of cyclicvoltammetry and pulse differentiation. WO₃nanowire is used to modify carbon pasteelectrode, the best ratio and optimal test conditions of which is discovered. Linearrange equation has been established to determine the density of honokiol and good reproducibility of electrode has been observed. Meanwhile, the same methods aresuccessfully applied to the determination of Magnolol and honokiol, the result ofwhich is consistent with the result of HPLC, relative deviation lower than5%and therecovery rate from96.5%to98.8%.The thesis can contribute to the determination and study of the main activeingredients of medicine by using nano-WO₃as a new kind of testing electrode. Suchtesting method is simple, rapid and accurate, which can provide accurate reference tothe drug dose control of active ingredients so that it can be better used in clinicalpractice.