The Research On The Electrochemical Behaviors Of Ascorbic Acid And Phenylacetic Acid At The Electrodes Modified By CuGeO₃ And Polyaniline/CuGeO₃ Nanowires

CuGeO3 nanowires and polyaniline/CuGeO3 nanowires exhibit excellent application potential for electrochemical sensors owing to their good electrochemical properties. The current research situation and recent development on the germanate nanowires, the application of nanowires for electrochemical sensors and the electrochemical analysis of the ascorbic acid and phenyl acetic acid have been discussed. Polyaniline/CuGeO3 nanowires have been obtained using CuGeO3 nanowires and polyaniline. The electrochemical behaviors of ascorbic acid and phenyl acetic acid at the CuGeO3 nanowire and polyaniline/CuGeO3 nanowire modified glassy carbon electrode(GCE). It is great significance for the modification of the CuGeO3 nanowires, electrochemical properties and the application for biological electrochemical sensors.Polyaniline/CuGeO3 nanowires with different polyaniline contents have been obtained using CuGeO3 nanowires and polyaniline by hydrothermal process. Electron microscopy analysis shows that the polyaniline particles in the polyaniline/CuGeO3 nanowires are composed of sphere-shaped morphology and have the diameter of less than 100 nm. The diameter of the CuGeO3 nanowires is about 50-150 nm. Polyaniline particles attach to the surface of the CuGeO3 nanowires. UV-vis spectrum shows that the polyaniline/CuGeO3 nanowires consist of a strong absorption peak at 224 nm. The amount of the polyaniline particles increase obviously with the increase of the polyaniline content.CuGeO3 nanowires and polyaniline/CuGeO3 nanowires can be firmly attached to the surface of the GCE. Two pairs of strong semi-reversible redox cyclic voltammogram(CV)peaks located at +0.2 V, +0.02 V(cvp1, cvp2) and +0.07 V,-0.34 V(cvp1′, cvp2′) are observed from the electrochemical CV curve of ascorbic acid at the CuGeO3 nanowire modified GCE. The intensity of the electrochemical CV peaks increases obviously with increasing the scan rate. The detection limit is 24 μM and 8.6 μM for cvp1 and cvp2,respectively and the linear range is 0.01-2 mM using CuGeO3 nanowire modified GCE.Two pairs of strong semi-reversible redox CV peaks located at +0.28 V, +0.42 V(cvp1,cvp2) and +0.05 V,-0.41 V(cvp1′, cvp2′) are observed from the CV curve of ascorbic acid at the 20 wt.% polyaniline/CuGeO3 nanowire modified GCE. The detection limit is 0.61μM and 0.26 μM for cvp1 and cvp2, respectively and the linear range is 0.001-2 mM. The intensity of the CV peaks increases obviously with the increase of the polyaniline content from 10 wt.% to 40 wt.%. The detect limit decreases from 6.4 μM(cvp1) and 1.8 μM(cvp2)to 0.35 μM(cvp1) and 0.14 μM(cvp2). The CuGeO3 nanowire and polyaniline/CuGeO3 nanowire modified GCEs exhibit good reproducibility and stability for the electrochemical determination of ascorbic acid.Two pairs of strong semi-reversible redox CV peaks located at +0.31 V,-0.02 V(cvp1,cvp2) and-0.10 V,-0.51 V(cvp1′, cvp2′) are observed from the electrochemical CV curve of phenyl acetic acid at the CuGeO3 nanowire modified GCE. The detection limit is 82.1μM and 9.1 μM and linear range is 0.1-2 mM and 0.01-2 m M for cvp1 and cvp2,respectively using CuGeO3 nanowire modified GCE. Electrochemical impedance spectroscopy of the polyaniline/CuGeO3 nanowire modified GCE shows smaller resistance than that of the CuGeO3 nanowire modified GCE and the charge transfer through the polyaniline/CuGeO3 nanowires is facile. Two pairs of strong semi-reversible redox CV peaks located at-0.02 V, +0.33 V(cvp1, cvp2) and-0.13 V,-0.39 V(cvp1′, cvp2′) are observed from the CV curve of phynyl acetic acid at the 40 wt.% polyaniline/CuGeO3 nanowire modified GCE. The detection limit is 8.2 μM and 4.3 μM for cvp1 and cvp2,respectively and the linear range is 0.01-2 mM. The detect limit decreases from 25.4 μM(cvp1) and 7.9 μM(cvp2) to 8.2 μM(cvp1) and 4.3 μM(cvp2) with the increase of the polyaniline content from 10 wt.% to 40 wt.%. The CuGeO3 nanowire and polyaniline/CuGeO3 nanowire modified GCEs exhibit good reproducibility and stability for the electrochemical determination of phenyl acetic acid.