| It has been reported that many biological small molecule levels are directly related to human health,and uric acid(UA)is one of the most typical small molecules among them.As an important antioxidant,UA helps maintain blood pressure and maintain the stability of oxidative stress.An abnormal UA concentration may be associated with many diseases:high UA levels may lead to high blood UA,gout and some cardiovascular diseases;low UA levels may result in some blood pressure and oxidative stress problems.Therefore,the level of UA in the human body is one of the important parameters of people's health.The increase in UA levels may come from abnormal lifestyles such as excessive purine intake and excessive alcohol consumption,besides,some genetic diseases may cause low levels of UA in the body for a long time.Nowadays people pay more and more attention to UA level detection,and it is urgent to develop a fast and accurate UA detection method.So far,many detection methods have been developed to measure UA levels in human serum and urine,and even saliva,nails and tears.Those methods including spectrum(ultraviolet,fluorescent),electrochemical(voltammetry,electrochemical luminescence,surface plasmon resonance),chromatography(liquid phase and gas phase),capillary electrophoresis and isotope dilution mass spectrometry,and so on.In recent years,thanks to the emphasis on conducting polymer research,conducting polymer-based UA sensors have developed rapidly.Polyaniline(PANI)and poly 3,4-ethylenedioxythiophene(PEDOT)are one of the most common and highly conducting conducting polymers.Based on them,this study explores electrochemical detection methods for small biological molecules such as UA.In this paper,different forms of PANI and PEDOT were polymerized by two methods,chemical synthesis and electrochemical synthesis,and their applications in the detection of small molecules such as UA were explored.1.Bionic synthesis of polyaniline microspheres and its application in the detection of uric acidIt is found for the first time that ferrocene(Fc)can be used as a peroxidase mimic enzyme to catalyse the oxidation of hydrogen peroxide(H2O2)in this experiment.Hydroxyl radicals(OH·),one product from the oxidation reaction,oxidizes 3,3',5,5'-tetramethylbenzidine(TMB,colorless solution)to TMBOX(blue solution).The double-reciprocal plots represent that the catalytic mechanism of Fc in H2O2 oxidation is consistent with the ping-pong mechanism.Additionally,Fc was successfully utilized for the PANI microspheres synthesis in the presence of H2O2.Compared with the control,better physical and chemical properties of PANI synthesized in the presence of Fc are found in this study.Manganese porphyrin doped PANI(Mn TCPP-PANI)was synthesized by this method and used in UA detection.Experiments show that Mn TCPP-PANI synthesized by this method has good signal response to UA detection.2.Electrodeposition of three-dimensional network nanostructure PEDOT/PANI for simultaneous voltammetric detection of ascorbic acid,dopamine and uric acidIn this study,PEDOT and PANI were electrodeposited via cyclic voltammetry(CV)on glass carbon electrode(GCE)layer by layer.The prepared electrode(GCE/PEDOT/PANI),was used for the simultaneous sensitive determination of ascorbic acid(AA),dopamine(DA)and UA at different oxidation potentials.The peak distances of AA and DA,DA and UA,AA and UA were 216 m V,104 m V,320 m V,respectively.For individual detection of AA,DA and UA,the linear ranges were 1×10-4-1×10-2 M,3×10-5-1×10-3 M and 7×10-7-1×10-4 M with detection limits of 2.42×10-5 M,4.58×10-6 M and 2.38×10-7 M(S/N=3),respectively.For simultaneous detection of AA,DA,and UA,the linear response ranges were 1×10-4-1×10-3 M,3×10-4-1×10-2 M,and 3×10-6-1×10-4 M with detection limits of 6.91×10-5 M,3.66×10-5 M and 4.13×10-7 M(S/N=3),respectively.The GCE/PEDOT/PANI displayed good selectivity,reproducibility and storage stability,and was further applied to the detection of AA,DA and UA in 5% normal human serum samples. |
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