Preparation And Analytical Application Of Gold Nanoparticles And Molybdenum Oxide Composite Film Modified Electrode

Highly sensitive detection toward glucose is very desirable due to its widespread application in the fields of clinical chemistry, biochemistry, environmental, glucose-oxygen fuel cells and food chemistry. Related to this is the sensing of saccharides which finds widespread exploitation in analytical and forensic applications. Since the first glucose sensing platform reported by Clark and Lyons, glucose oxidase (GOx) based and glucose dehydrogenase (GDH) based glucose sensing platform have been widely used in the detection of blood glucose. However, a number of critical drawbacks hinder its further development. In view of the nature of the enzymes, the most common and serious problem concerning the enzymatic glucose sensing platforms lies in their rigorous operational conditions (such as solution acidity, temperature, etc.) and the intrinsic instability. In addition, the use of expensive enzyme is also unfavorable in term of cost-effectiveness. To solve this problem, many non-enzymatic glucose sensing platforms have also been explored in the hope of improving the electrocatalytic activity and selectivity towards the oxidation of glucose. This research aims to develop novel electrochemical sensor for saccharides, and applied to the determination of antineoplastic.Two main aspects were as follows:1. The MoOx/AuNPs composite film modified glassy carbon electrode was fabricated by electro-depositing simultaneously gold nanoparticles and molybdenum oxides using cyclic voltammetry. The morphology and topography of the MoOx/AuNPs composite were characterized by scan electron microscopy and X-ray photoelectron spectroscopy respectively, and the electrocatalytic oxidation of glucose at the MoOx/AuNPs composite film was investigated and analyzed in detail. It was shown that the MoOx/AuNPs composite was of strong electrocatalytic activity towards oxidation of glucose as well as other saccharides, so that an attempt was made for direct voltammetric determination of glucose. Then the positive scan polarization reverse catalytic voltammetry was proposed for the first time. Based on this method, the pure oxidation current was extracted by subtraction of the blank current in the reverse scan. Resulting in that the current sensitivity was enhanced tremendously and the signal to noise ratio was improved adequately. The electrocatalytic oxidation of glucose at the MoOx/AuNPs modified electrode was performed in alkaline medium, a wide linear range from0.01to4.0mM of glucose, a higher current sensitivity of2.35mA·mM-1·cm-2, and a lower detection limit of9.01μM (at signal/noise=3) were achieved. In addition, the electrocatalytic oxidation of other saccharides such as lactose, fructose and sucrose and the determination of glucose injection were also evaluated.2. Applied MoOx/AuNPs composite film modified glassy carbon electrode to the determination of antineoplastic. The MoOx/AuNPs composite film modified glassy carbon electrode was fabricated by electro-depositing simultaneously gold nanoparticles and molybdenum oxides using cyclic voltammetry. The morphology and topography of the MoOx/AuNPs composite were characterized by scan electron microscopy and X-ray photoelectron spectroscopy respectively, and the electrocatalytic oxidation of these antineoplastics at the MoOx/AuNPs composite film was investigated and analyzed in detail. Then the positive scan polarization reverse catalytic voltammetry was applied to detect these antineoplastics and the sensor exhibited a wide linear range, good sensitivity and low detection limit. We also investigated the determination application of calcium folinate injection.