The Application Of Novel Nanomaterials In Electrochemical Biosensor

This paper mainly studied the synthesis of three different kinds of nanocompositesincluding of FeTCPP-GR nanocomposite, FeTCPP-Ti0.7W0.3O2nanocomposite andgraphene/doped tungsten titanium dioxide nanocomposite and their catalysis of oxygen,hydrogen and glucose. The main research content includes the following three parts:(1) FeTCPP-GR nanocomposite material was prepared by the assembly ofiron-tetra(4-carboxyphenyl)porphyrin (FeTCPP) macrocyclic molecules on the reducedgraphene oxide (GR) surface by π-π stacking interactions. The as-prepared FeTCPP-GRnanocomposite material was characterized by ultraviolet–visible absorption spectroscopy(UV–Vis) and Fourier transform infrared spectroscopy (FTIR). The electrocatalytic oxygenreduction reaction (ORR) of the nanocomposite material was studied by cyclic voltammetry(CV) and compared with that of FeTCPP. It showed that the two electrode reactionsproceeded in different mechanisms. The FeTCPP modified electrode electrocatalyticallyreduced oxygen in two steps which involved two electrons respectively. However, theFeTCPP-GR modified electrode reduced oxygen in one step which involved four electrons.The FeTCPP-GR nanocomposite material was prepared for oxygen sensor based on itsexcellent electrocatalytic activity for oxygen reduction. The response current was linear to O2concentration with the concentration range from0.627to6.27mg/L (R=0.997). The detectionlimit was0.13mg/L (S/N=3).(2) A novel hydrogen peroxide electrochemical biosensor without enzyme was developed. Itwas based on the film of FeTCPP-Ti0.7W0.3O2nanocomposite material which was prepared bythe assembly of iron-tetra(4-carboxyphenyl)porphyrin (FeTCPP) macrocyclic molecules onthe doped tungsten titanium dioxide(Ti0.7W0.3O2) surface with rutile phase via electrostaticinteractions. The electrocatalytic H2O2reduction reaction of the nanocomposite material wasstudied by cyclic voltammetry (CV). It showed that the FeTCPP-Ti0.7W0.3O2nanocompositematerial was prepared for H2O2sensor based on its excellent electrocatalytic activity for H2O2reduction. The response current was linear to H2O2concentration with the concentration rangefrom5.0×10-7mol/L to1.2×10-5mol/L (R=0.997). The detection limit was1.1×10-8mol/L(S/N=3).(3) A novel graphene/doped tungsten titanium dioxide rutile phase compound film modifiedelectrode was prepared through drops of coating method and electrochemical reduction. Theglucose biosensor was constructed by fixing glucose oxidase to the electrode surface and study the direct electrochemistry of glucose oxidase and the sensor’s detection of glucose. Theresults showed that graphene/doped tungsten titanium dioxide with rutile phase compositefilm modified electrodes can keep the structure of the glucose oxidase and bioelectricitycatalytic activity well, promoting the direct electron transfer of modified electrodes and thegood catalytic oxidation of glucose. The Glucose oxidase on the modified electrodes of theelectron transfer rate constant Ksis2.11s-1and the determination of glucose in the linearrange is0.1～10mM (R2=0.992), detection limit is0.014mM (S/N=3). The sensor hasgood electrical conductivity, selectivity, reproducibility and stability, and can be applied to theanalysis of actual sample detection.