Simultaneous Determination Of Medicines And Biological Molecular By Carbon Nanomaterials Modified Electrodes

Carbon nanomaterials are widely used in the preparation of novel electrochemical sensors due to their excellent electrochemical properties.In this study,the electrocatalytic performance of carbon nanomaterials was improved by changing the structure of carbon nanomaterials or compounding two kinds of carbon nanomaterials.Then,two chemically modified electrodes have been prepared based on the as-prepared carbon nanomaterials for simultaneous determination of various substances.The main contents are as follows:1.In this study,the multi-walled carbon nanotubes aerogel(MWCNTs-aerogel)was prepared by ultrasonication and freeze-drying method.Then,the aerogel was dissolved in a 0.1%Nafion solution to obtain a suspension.The suspension was dropcasted on the glassy carbon electrode surface to construct the MWCNTs-aerogel/Nafion modified electrode.The morphology of MWCNTs aerogel was examined by scanning electron microscopy.The electrochemical responses of the sensor were studied by cyclic voltammetry and differential pulse voltammetry.The results show that the MWCNTs-aerogel/Nafion modified electrode has excellent electrocatalytic activity for the redox of levodopa(LD),acetaminophen(AC)and L-tyrosine(Tyr),which can be used to simultaneously determine the above three kinds.substances.The linear ranges for detection of LD,AC and Tyr were 2.0-300.0 μmol/L,2.0-180.0 μmol/L,and 2.0-120.0 μmol/L,with the detection limit of 0.6 μmol/L,0.5 μmol/L and 0.8 μmol/L(S/N=3),respectively.Finally,the sensor was applied to detect LD,AC and Tyr in serum sample,and the results were satisfactory.2.Multi-walled carbon nanotubes(MWCNTs)and ordered mesoporous carbon(OMC)were dissolved in 0.1%chitosan solution to form a uniform stable suspension.Then the suspension was dropcasted onto the glassy carbon surface to prepare MWCNTs/OMC/Chitosan modified electrode.The morphology of multi-walled carbon nanotubes/ordered mesoporous carbon composite was examined by scanning electron microscopy.The electrochemical impedance spectroscopy,cyclic voltammetry and differential pulse voltammetry were used to investigate the electrochemical properties of the MWCNTs/OMC/Chitosan modified electrode.The results show that multi-walled carbon nanotubes/ordered mesoporous carbon composite membrane combines the advantages of two carbon nanomaterials,and has obvious catalytic effects on the electrochemical reactions of uric acid(UA)and cefotaxime sodium(CEF).The better peak separation effect and larger oxidation peak current responses can be obtained at the MWCNTs/OMC/Chitosan modified electrode.And the resulting modified electrode could be used for simultaneous determination of UA and CEF.The linear response range of UA and CEF is 10.0-350.0 μmol/L and 10.0-240.0 μmol/L,and the detection limits are 0.2 μmol/L and 0.4 μmol/L(S/N=3),respectively.The chemically modified electrode could be used to detect UA and CEF in serum samples.