Preparation Of Ag@C Core-shell Material And Its Application On Electrochemical Sensors

ObjectiveDopamine(DA)is an important neurotransmitter in the central nervous system of mammals.The lack of DA can lead to neurological diseases,such as schizophrenia and Parkinson's disease.Metronidazole(MNZ)is a commonly used antibiotic drug,but excessive use can cause optic neuropathy and genetic toxicity,which endangers health.Considering that the content of DA and MNZ will have an impact on health,it is important to establish a detection method that is simple,sensitive and analytically reliable.So far,various analytical methods such as atomic absorption,high-performance liquid chromatography and fluorescence have been used to detect DA and MNZ.The above-mentioned detection methods have a wide range of applications and accurate detection results,at the same time,they also have high cost,long time-consuming and other limitations.Electrochemical sensors can overcome the above-mentioned obstacles and have the advantages of low cost,easy operation and high sensitivity.Reduced graphene oxide(RGO)has the advantages of high conductivity and large specific surface area.Nitrogen-doped reduced graphene oxide(N-RGO)can effectively improve the reactivity and surface energy of the carbon skeleton.Multi-walled carbon nanotubes(MWCNTs)have high electrical conductivity and strong mechanical properties.Ag@C has the advantages of two single materials and has greater advantages in the amplification and detection of electrochemical signals.In this paper,Ag@C/MWCNTs and Ag@C/N-RGO-MWCNTs were prepared and applied to the surface of electrodes to construct DA and MNZ electrochemical sensors and discuss their electrochemical performance.MethodsAg@C and N-RGO-MWCNTs were prepared by hydrothermal method.The Ag@C was characterized by transmission electron microscopy(TEM)and X-ray diffraction(XRD).The elements of N-RGO-MWCNTs were analyzed by energy dispersion spectroscopy(EDS).The dopamine electrochemical sensor constructed by Ag@C/MWCNTs and the metronidazole electrochemical sensor constructed by Ag@C/N-RGO-MWCNTs were studied by cyclic voltammetry(CV)and linear sweep voltammetry(LSV)respectively.ResultsAg@C/MWCNTs/GCE showed excellent electrochemical activity for DA solution in 0.5?80?mol/L concentration range.There is a certain linear relationship between concentration and current.The detection limit is 1.45×10^-8mol/L.The linear range of Ag@C/N-RGO-MWCNTs/GCE for the determination of MNZ content is 0.1?150?mol/L.The detection limit(S/N=3)is 4.41×10^-8mol/L.It has good stability and can be used for the determination of metronidazole in actual drugs.ConclusionsAg@C and N-RGO-MWCNTs were successfully prepared by hydrothermal method.The Ag@C/N-RGO-MWCNTs were prepared by ultrasonic mixing.Ag@C and MWCNTs were mixed ultrasonically and modified on the surface of glassy carbon electrode.By electrochemical detection of DA solution,Ag@C/MWCNTs/GCE showed good electrochemical activity within a certain range with stability and reproducibility.It also provides an ideal application prospect for the preparation of dopamine electrochemical sensors.The Ag@C/N-RGO-MWCNTs/GCE shows good electrochemical activity in MNZ solution,which can be used for the detection of actual samples.