| Summary: | 碩士 === 國立臺灣大學 === 高分子科學與工程學研究所 === 105 === In this study, a simple strategy to prepare copper oxide/montmorillonite nanocomposite used for nonenzyme glucose detector was developed. By following the method published in the literature, we successfully prepared the CuO/GO/GCE electrode by using hydrothermal method. At the applied potential of 0.55V, the CuO/GO/GCE electrode presented a high sensitivity of 3576 (μA/mM cm2), linear range of 0.01-6 mM, detection limit of 10 M. In this research, the CuO nanoparticle was blended with exfoliate montmorillonite (exMMT) which could enhance the oxidation of metal ions and muti-walled carbon nanotube (CNT) which could improve the conductivity of CuO, and applied in non-invasive detection of glucose in saliva and urine. The surface morphology of as-prepared nanocomposites was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Electrochemical measurements including cyclic voltammetry (CV), chronoamperometry, and electrochemical impedance spectroscopy (EIS) were employed to estimate their sensibility.
First, CuO in monoclinic phase were prepared by Cu(NO3)3 and Cu(OAc)2 with diameter of 10 nm and 5 nm respectively which were characterized by XRD and TEM. Because of the aggregation of CuO in nature, glucose cannot diffuse into the porous surface of electrode to obtain the desirable electrochemical performance. When employing the appropriate concentration of exMMT, CuO can be effectively disaggregated. Therefore, CuO/exMMT prepared by Cu(OAc)2 was used for further studies in this research. According to the past research in our laboratory, Mg ion of exMMT could accelerate the oxidation of metal ion, and the XPS result also showed the exMMT would release the Mg ions to oxidase Cu ions in the CuO/exMMT composite, which may lead to the 3D porous structure.
CuO/CNT were also fabricated by hydrothermal process. The CuO of CuO/CNT was in monoclinic phase with the particle size about 5 nm. Under the appropriate concentration of CNT, CuO can be disaggregated by CNT and improved composite’s conductivity. The result showed CuO/CNT (3.1wt%) composite had the best performance in the CuO/CNT system.
Next, because the CuO/exMMT (0.4wt%) system had the highest sensitivity, we further incorporated different amount of CNT with the control of addition time to enhance the performance of composite electrodes. The results indicated that CuO/exMMT (0.4wt%), CuO/CNT (3.1wt%) and CuO/exMMT(0.4wt%)/CNT (2.1wt%) have the excellent performance in the glucose detection with sensitivity of 3582、3468、3654 (μA/mM cm2) at the applied potential of 0.55V.
Moreover, these three electrodes can be used to determine the glucose concentration in urine. The interfering test showed the good selectivity of CuO, CuO/GO, CuO/exMMT(0.4wt%), CuO/CNT(3.1wt%), and CuO/exMMT(0.4wt%)/CNT(2.1wt%) electrodes toward glucose blending with common interfering species, such as ascorbic acid, uric acid, dopamine etc. Althought the sensitivity of these electrodes for the interfering species are almost the same as glucose, the concentration of interfering species in blood or urine is very low and will not interfere with the detection of glucose.
Therefore, this research has demonstrated a simple and effective method to fabricate CuO nanocomposite electrodes for nonenzymatic detection of glucose.
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