Electrochemical Detection Of Dopamine,Nitrite Ion,Uric Acid Based On Nanocomposite Modified Electrodes

Dopamine,nitrite ion,uric acid and other substances in the process of life activity plays a very important role.Abnormal levels of dopamine,nitritr ion,uric acid often changes in metabolic mechanism.Such as changes concentration of dopamine will affect the nervous system of person;on the one hand nitrite ion can affect the oxidation of hemoglobin,on the other hand will promote or inhibit the release of dopamine;uric acid leads to human body metabolic diseases.Therefore,based on some high sensitivity,good selectivity electrochemical sensor used for the quantitative detection of the material is very necessary.Combined with functional nano materials,this paper using electrochemical method for sensitive detection of dopamine,nitrite ion,uric acid.Specific work is as follows:An ionic liquid-titanium dioxide /gaphene oxide composite modified electrode glass carbon electrode(GCE)was constructed by modifying the surface of GCE with GO,then electrodeposition ionic liquids(IL,[BMIM]BF4)-titanium dioxide(Ti O2)nanometer materials.The surface morphologies of different modified electrodes like bare GCE,GO/GCE,TiO2/GO/GCE,IL-TiO2/GO/GCE were characterized by scanning electron microscopy(SEM),their corresponding differential pulse voltammetry(DPV)and Cyclic voltammetry(CV)behaviors were investigated,indicating that the composite of IL-TiO2/GO exhibited excellent electrocatalytic oxidation activity to dopamine(DA)molecule.In 0.10 mol/L of PBS buffer solution(pH=6.0),the modified electrode showed nice electrochemical response property to DA with a linear range of 8.0×10-9~ 6.0×10-5mol ? L-1 and a detection limit of9.62×10-10mol?L-1(S/N=3).The electrode possessed good selectivity,reproducibility and stability,which can be well applied to determination of DA in human serum samples with a recovery rate of 98.6%~103.2%.Compared with traditional spectrophotometric method,the proposed method has been of valuable in practical application on biomedical analysis field.Using poly(dienedimethylammonium chloride)(PDDA)as the protective and reductive agent,and combining with graphene oxide(GO),the PDDA functionalized cubic silver nanoparticles(C-AgNPs)/ GO composite was prepared and then modified on a glassy carbon electrode(GCE)to form C-AgNPs-PDDA/GO/GCE.The surface morphologies of different modified electrodes were characterized by scanning electron microscope(SEM),and their corresponding cyclic voltammograms(CV)behaviors were investigated,indicating that the composite of C-AgNPs-PDDA/GO exhibited excellent electrocatalytic oxidation activity to DA and NO2-.By using differential pulse voltammetry,the response of C-AgNPs-PDDA/GO/GCE to DA and NO2-were linear in the range of 0.030 ~ 0.300μmol/L,0.300 ~ 300.0μmol/L and 30.0~ 2300.0μmol/L with detection limits of 9.8nmol/L and 12.6μmol/L(S/N = 3),respectively.The modified electrode displayed good selectively,reproducibility and stability,which can be used for determination of DA and NO2-in human serum samples with recoveries of 97.4~104.2% and 98.0~102.8%,respectively.Compared with spectrophotometric method,the determination results are satisfactory,showing that the modified electrodes have a potential application value.Sodium dodecyl sulfate functionalization graphene oxide(SDBS-GO)/ copper oxide-copper(CuO-Cu)modified electrode glass carbon electrode(GCE)was constructed by modifying the surface of GCE with SDBS-GO,and then electrodeposition CuO-Cu nanometer materials.The microstructure of different composite membrane was discussed using scanning electron microscope(SEM).The modified electrodes showed good catalytic performance for UA due to the synergistic effect of SDBS-GO and CuO-Cu.In the of phosphate buffer solution(PBS,0.10 mol/L,pH = 6.0),the modified electrodes had good linear relationship for UA within 2.0×10-8~ 6.0×10-6mol?L-1 and 6.0×10-6~ 166.0×10-6 mol?L-1,detection limit of 9.04×10-9 mol?L-1(S/N = 3).In addition,the modified electrode displayed good anti-jamming,reproducibility and stability,which can be used for determination of UA in human serum samples with recoveries of 96.0%~103.8%.Compared with uric acid enzyme method,the determination result is satisfactory.