| As a new member of carbon materials such as graphene and carbon nanotubes have gradually become the research focus since the discovery of graphene by scientists in 2004.When the two materials are combined into a new type of composite material,the unique properties of the nano-composite material are widely used in many fields.In this paper,a new type of carbon/metal nano-composite modified electrode is prepared by using carbon nanocomposites as the base doped metal nanoparticles,and its application in chemical analysis is explored.1.Determination of L-Tryptophane at graphene/multi walled carbon nanotube modified carbon fiber electrodeCyclic voltammetry was used to investigate the properties of carbon fiber electrode in this paper.The electrochemical behavior of glassy carbon electrode and carbon fiber electrode in potassium ferricyanide was investigated,and the properties of glassy carbon electrode and carbon fiber electrode were compared.The results showed that the carbon fiber electrode had good electrochemical performance.This paper was prepared graphene oxide and multiwall carbon nanotube composite materials.The ERGO-MWCNTs carbon fiber electrode was obtained by drop coating method and electrochemical reduction method.The electrochemical behavior of L-tryptophan on the modified electrode was studied.The experimental results showed that compared with bare carbon fiber electrode,and the oxidation peak current is enhanced by about 8.5 times.In phosphate buffer of pH 6.0,the oxidation peak currents were linearly dependent on the L-Trp concentrations in the range of 5.00×10-6-1.00×10-44 mol/L with concentration time of 250 s and scan rate of 100 mV/s.The correlation coefficient was0.993 and the detection limit was 6.41×10-77 mol/L.2.Determination of glucose at Ni-Cu nanoparticles/ERGO-MWCNTs-Nafion composite modified electrodeIn this work,the Ni2+?Cu2+nanoparticles?Ni-Cu NPs?are deposited on GO-MWCNTs-Nafion sheets,at last a Ni-Cu NPs/ERGO-MWCNTs-Nafion modified flassy carbon electrode has been fabricated.The results show that this composite modified film has a good effect on the catalytic oxidation of glucose.A novel nonenzymatic glucose sensor based on a glass carbon electrode modified with Ni-Cu NPs/ERGO-MWCNTs-Nafion?referred to as Ni-Cu NPs/ERGO-MWCNTs-Nafion/GCE?displays an enhanced electrocatalytic activity to glucose oxidation in 0.2 M NaOH solution than that of Ni/ERGO-MWCNTs-Nafion/GCE?Cu/ERGO-MWCNTs-Nafion/GCE?Ni-Cu NPs/Nafion/GCE,respectively.At an applied potential of0.45 V,glucose measurements showed excellent linear reaponse,ranging from 4.00×10-7-9.20×10-5 mol/L and 9.20×10-5-1.9×10-3 mol/L.The detection limits were found to be1.58×10-7 mol/L.The proposed method can be used for the determination of actual sampals.3.Determination of glycine at Co nanoparticles/grapheme-multi walled carbon nanotube modified electrodeIn this paper,cobalt nanoparticles were deposited on graphene-MWCNTs modified glassy carbon electrode by electrochemical polymerization,and accordingly a new glycine electrochemical sensor was developed.Glycine measurements showed excellent linear respose,ranging from 5.00×10-5-1.00×10-3 mol/L and 1.00×10-3-1.00×10-2 mol/L?r=0.996?r=0.993?.The detection limits were found to be 1.35×10-5 mol/L.The resulted sensor displayed a good electrocatalytic activity for the oxidation of glycine and with a high sensitivity and well stability. |
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