Preparation And Application Of Cerium Compound Nanoparticles Modified Electrode

Rare earth elements usually exhibit special optical and chemical properties.In recent years,attention has been paid to rare earth nanoparticles for their preparation and applications as luminous material, catalysts,electronic ceramics,glass polisher,and etc.In this paper we present a study on rare earth nanoparticles modified electrode.It may provid a good example of applying the good catalysis of rare earth and nanoparticles to electrochemistry.First,a glassy carbon electrode modified with CeO₂ nanoparticles was constructed and was characterized by electrochemical impedance spectrum(EIS)and cyclic voltammetry(CV).The resulting CeO₂ nanoparticles modified glassy carbon electrode was used to detect uric acid(UA)and ascorbic acid(AA)simultaneously in mixture.This modified electrode exhibited potent and persistent electron-mediating behavior followed by well-separated oxidation peaks towards UA and AA with activation overpotential.For UA and AA in mixture,one can well separate from the other with a potential difference of 273mV,which was large enough to allow the determination of one in presence of the other. The proposed method showed excellent selectivity and stability,and the determination of UA and AA simultaneously in serum was satisfactory.Secondly,the CeHCF and MWNTs were modified onto the glassy carbon electrode to fabricate the modified electrode.Electrocatalytic oxidation of tryptophan at the CeHCF/MWNT/GC electrode was studied. And it had been applied to the determination of tryptophan in pharmaceutical samples with satisfactory results.The reliability and stability of the CeHCF/MWNT/GC electrode offered a good possibility for applying the technique to routine analysis of trptophan in clinical use.Thirdly,combining the properties of multi-wall carbon nanotubes with the good catalysis of CeO₂,a CeO₂/MWNT modified glassy carbon electrode was constructed.Transmission electron microscopy and X-ray data was used to observe the nanoparticles CeO₂/MWNT.The CeO₂/MWNT/GC electrode showed potent electrocatalytic activity toward the electrochemical oxidation of guanine and adenine.The proposed method showed excellent selectivity and stability,and the determination of guanine and adenine simultaneously in ssDNA(signal strand DNA)and acid-denatures DNA was satisfactory.These results may help us to develop a new method for the simultaneously determination for guanine and adenine in DNA.And the distinguishing between ssDNA and dsDNA become easy.At last,CePW nanoparticles supported on multi-wall carbon nanotubes was prepared,and it was modified onto a glassy carbon electrode then.Cyclic voltammetry(CV)and electrochemical impedance spectroscopy(EIS)were used to characterize the electrode modifying process.The electrochemical behavior of dopamine on this modified electrode was investigated and the result shows that it also can eliminate the interference of ascorbic acid and then dopamine can be determined selectively.It was applied in the sample determination and the result is satisfied with us.