Preparation And Application Of Sensors Based On Ionic Liquid Functionalized Carbon Nanotube

Recently, some research groups have focused on the application of carbonnanotubes （CNTs） in biosensor systems. CNTs can be used as modefied electrode dueto its virtue of outstanding electronic properties. Another material is Ionic liquids （IL）.Because of good ionic conductivity and relatively wide electrochemical window, theyhave been extensively used as electrochemical solvents as well as electrolyte.Especially, functionalized carbon nanotubes with ionic liquids play an active role inpromoting the development of electrochemical analysis, and to promote thedevelopment of biological and electrochemical interdisciplinary field. Thisdissertation describes the preparation and application of IL-functionalized carbonnanotubes sensor.The main contents are summarized as follows:1. In this chapter, the electrochemical behaviors of Hydroquinone （HQ） and catechol（CC） at the MWNTs-IL/glassy carbon electrode （GCE） were investigated. MWNTs-IL/GCE, a glassy carbon electrode modified with multiwalled carbon nanotubes（MWNTs） and ionic liquids （IL）, was developed to serve as a sensor for simultaneousdetermination of Hydroquinone （HQ） and catechol （CC）. The modified GCE showedtwo well-defined redox waves for HQ and CC in both CV and DPV with a peakpotential separation of ca.0.1V, which was large enough for simultaneous detection.The results revealed that the oxidation of HQ and CC with the enhancement of theredox peak current and the decrease of the peak-to-peak separation exhibit excellentelectrocatalytic behaviors. A high sensitivity of1.8×107M with detection limits of6.7×10^-8M and6.0×10^-8M （S/N=3） for HQ and CC were obtained. Moreover, theconstants of apparent electron transfer rate of HQ and CC at MWNTs-IL/GCE werecalculated as7.402s^-1and8.179s^-1, respectively, and the adsorption quantity of HQand CC was^-1.408×10^-6mol cm^-2with chronocoulometry. The developed sensor canbe applied to determinate directly of HQ and CC in aqueous solution.2. Here we report on a new approach for the electrochemical detection of hydrogenperoxide （H2O2） based on Cytochrome C （Cyt c） immobilized ionic liquid （IL）- functionalized multi-walled carbon nanotubes （MWNTs） modified glass carbonelectrode （GCE）. Functionalization of multi-walled carbon nanotube withamine-terminated ionic liquid materials were characterized using fourier transforminfrared spectroscopy （FTIR）， UV–vis spectra, and electrochemical impedancespectroscopy （EIS）. Amperometry was used to evaluate the catalytic activity of thecyt c towards H2O2.The proposed biosensor exhibited a wide linear response rangenearly4orders of magnitude of H2O2(4.0×10^-8M-1.0×10^-4M) with a good linearity（0.9980） and a low detection limit of1.3×10^-8M （based on S/N=3）. Furthermore, thebiosensor also displays some other excellent characteristics such as high selectivity,good reproducibility and long-term stability. Thus, the H2O2biosensor constructed inthis study has great potential for detecting H2O2in complex biosystems.3. Direct electrochemistry of cytochrome c （Cyt c）, which was adsorbed on thesurface of functionalization of multi-walled carbon nanotubes （MWNTs/IL）, wasinvestigated. The results from electrochemical impedance spectroscopy （EIS） anddifferential pulse voltammetry （DPV） suggested that an obvious promotion for thedirect electrotransfer between Cyt c and electrode.