Set And Its Applications, Chemically Modified Electrode Structure Of Ionic Liquids Based On Imidazole And Pyridine

Ionic liquids are organic salts consisted of only ions utterly, which are liquids with the melting point close to or below room temperature. The unique physical and chemical properties make them suitable for many applications. In this thesis, ionic liquid carbon paste electrodes (CILEs) and eight kinds of chemically modified electrodes are fabricated based on imidazolium and pyridinium ionic liquids. The electrochemical behaviors of four compounds, and direct electrochemistry and electrocatalytic activity of four proteins (enzyme) are investigated in details. The studies are significant to broaden the application range of ionic liquids, enrich research content of chemically modified electrodes and biosensors. The thesis consists of four chapters. The author's main contributions are summarized and presented as follows:Iimidazolium ionic liquid carbon paste electrode (CILE) and Nafion/L-aspartic acid/CILE are fabricated using hydrophobic ionic liquid, 1-butyl-3-methyl-imidazolium hexafluorophosphate ([BMIM][PF₆]) as binder. Electrochemical behaviors of dopamine (DA), nitrendipine (NT), paracetamol (PCT) are studied at these electrodes, respectively and corresponding differential pulse voltammetric determination methods are established. In terms of electron transfer, reversibility and sensitivity, CILEs are superior to traditional carbon paste electrode (TCPE) except for larger background current.Pyridinium ionic liquid carbon paste electrode (CILE) is fabricated using hydrophobic ionic liquid, 1-butyl pyridinium hexafluophosphate ([BPy][PF₆]) as binder. The electrochemical behaviors of ethamsylate (ESL) are investigated at CILE and a novel cyclic voltammetric determination of ESL in urine and serum sample is established. By casting and electrodeposit, GOx/CILE, Mb/CILE, Hb/Fe₃O₄/CILE and PB/Au/CILE are fabricated on the basis of CILE, which are used to investigate the direct electrochemistry and electrocatalytic activity of GOx, Mb and Hb, respectively. The corresponding cyclic voltammetry and amperometry are used to determine glucose and H₂O₂. The results show that [BPy][PF₆] can improve the properties of electrode and lower background current.Three kinds of new composites of HA-MWNTs-[BMIM][BF₄], HA-[CePy][PF₆] and GG-[BMIM][BF₄] are used as immobilization matrix to entrap GOx, Mb and HRP. By casting the mixture on the surface of GCE, HA-MWNTs-[BMIM][BF₄]-GOx/GCE, HA-[CePy][PF₆]-Mb/GCE and GG-[BMIM][BF₄]-HRP/GCE chemically modified electrodes are fabricated, respectively. Electrochemical and spectroscopy methods are used to characterize the composite films and the modified electrodes. The results show that GOx, Mb and HRP molecules in the composite films retain their native structures and achieve their direct electrochemistry. The chemically modified electrodes show excellent electrocatalytic activity toward glucose and H₂O₂. The catalytic currents are linearly with concentration of glucose and H₂O₂ in the fixed range. The cyclic voltammetry and amperometry are applied determine glucose and H₂O₂.