Preparation Of Carbon Nanomaterials And Biological Molecule Polymer Modified Electrodes And Their Analytical Applications

Electrochemical methods provide an effective platform for further undertanding the basic characters of the chemical reactions because they can study the interfacial charge transfer at the atomic and molecular levels.The construction of distinctive and high performance electrochemical sensors,as a main investigation theme,have become one of the hot research directions.As core components of the chemical sensor,selection of the electrode modified materials and fabrication of the chemical modified electrode are a key to prepare excellent proformance of electrochemical sensor.Nanocarbon materials,owing to their particular structure and properties,have attracted a great deal of interests in supercapacitor and electrochemically sensing fields.And the biomolecule polymers,because of their good film-forming properties and conductivity,have also become the darling of the electrode modified materials.In this theses,three kinds of highly sensitive,highly catalytically active and highly conductive chemically modified electrode with big specific surface area were prepared,based on the large specific surface area,good biocompatibility and excellent conductivity of carbon nanomaterials,and good film-forming properties of biomolecules,used for the analysis of phenolic organic matters.The main investigation contents consisted of four parts as follows:1.Electrochemical sensors were summarized and preparation methods and properties of the chemically modified electrode and relative electrode modified materials were discussied in detail.2.A novel poly-L-leucine/DNA composite membrane modified electrode（P-L-LEU/DNA/GCE）was successfully prepared by a simple and rapid electropolymerization combined with electrodeposition based on the excellent film-forming properties and high active sites of L-leucine and DNA.Scanning electron microscopy（SEM）and electrochemical impedance spectroscopy（EIS）were respetively employed to characterize the morphologies and electrochemical properties of the modified electrode.The electrochemical behaviors and redox reaction mechnism of acetaminophen（AC）on different modified electrodes were studied detailedly by cyclic voltammetry（CV）and differential pulse voltammetry（DPV）.The results showed that the prepared poly-L-leucine/DNA modified electrode displayed good electrical catalytic ability toward oxidation of AC.In p H=6.0 PBS suffer,the oxidation peak current of AC was directly proportional to its concentration in the ranges of 0.7¹0μmol·L^-1 and 10²50μmol·L^-1 respectively with a detection limit down to 2.3×10^-9 mol·L^-1.The proposed method was applied to the detection of acetaminophen in the real drug sample and satisfactory results were obtained.3.MWCNT@GONRs nanomaterial was at first prepared by a longitudinal cutting method successfully.And then,in order to improve dispersibility and stability of the prepared carbon nanomaterial,it was further functionalized by a non-covalent interaction of SDBS and MWCNT@GONRs.The resulted material SDBS-MWCNT@GONRs were characterized by scanning electron microscopy（SEM）,infrared spectroscopy（FT-IR）and Raman spectroscopy（Raman）.Finally,an electrochemical sensorfor simultaneously determination of hydroquinone（HQ）and catechol（CC）was successfully fabricated using this material by a simple drop-coating method and the redox reaction mechanism and electrochemical behaviors of these two analytes on the sensing platform were studied.The sensorwas used for simultaneous determination of HQ and CC in tap water and the Yellow River water of Lanzhou with satisfactory results.4.A novel,sensitive and selective poly-L-Arginine（P-L-Arg）/electroreduction graphene modified electrode（P-L-Arg/ERGO/GCE）was prepared by a simple electrochemically polymerization of L-arginine on graphene substrate obtained through electroreduction.And using the resulted modified electrode,hydroquinone and catechol were simultaneously determined by DPV in pH 7.0 PBS suffer solution.The results showed that the concentrations of hydroquinone and catechol were linear with their oxidation peak currents respectively.The detection limits were 1.67×10^-7mol·L^-1 and2.33×10^-7mol·L^-1,respectively.This modified electrode still showed excellent repeatability and good long-term stability and could be used to detect simultaneously hydroquinone and catechol in environmental water samples.