ABSTRACT
In the present work,a chemically modified electrode has been fabricated utilizing Bi2O3/ZnO nano-composite.The nanocomposite was synthesized by simple sonochemical method and characterized for its structural and morphological properties by using XRD,FESEM,EDAX,HRTEM and XPS techniques.The results clearly indicated co-existence of Bi2O3 and ZnO in the nanocomposite with chemical interaction between them.Bi2O3/ZnO nanocomposite based glassy carbon electrode(GCE)was utilized for sensitive voltammetric detection of an anti-biotic drug(balofloxacin).The modification amplified the electroactive surface area of the sensor,thus providing more sites for oxidation of analyte.Cyclic and square wave voltammograms revealed that Bi2O3/ZnO modified electrode provides excellent electrocatalytic action towards balofloxacin oxidation.The current exhibited a wide linear response in concentration range of 150-1000 nM and detection limit of 40.5 nM was attained.The modified electrode offered advantages in terms of simplicity of preparation,fair stability(RSD 1.45％),appreciable reproducibility(RSD 2.03％)and selectivity.The proposed sensor was applied for determining balofloxacin in commercial pharmaceutical formulations and blood serum samples with the mean recoveries of 99.09％and 99.5％,respectively.
ABSTRACT
Through a series of chemical reactions, a kind of quaternary ammonium salt derivative of nanodiamond, ND-CO-NH-CH2-CH2-N ( CH3 ) 3+· I-( QAS-ND ) , was obtained , which was confirmed by FTIR, element analysis experiment and the electrochemistry measurements. Mixed myoglobin ( Mb) and QAS-ND solution was dropped on the surface of the glassy carbon ( GC ) electrode to prepare QAS-ND/Mb/GC modified electrode. In 0. 1 mol/L phosphate buffer solution (PBS) (pH 7. 0), Mb in the membrane exhibited direct electrochemical properties and showed good stability. The electrocatalytic property of the modified electrode toward H2 O2 was investigated, the results showed that the modified electrode could be used as the H2O2 biosensor to achieve fast, accurate detection of H2O2, with a detection limit of 3. 5 mmol/L (S/N=3).
ABSTRACT
Praseodymium hexacyanoferrate film was modified on the graphite electrode by cyclic voltammetry in the solution of PrCl_3 and K_3Fe(CN)_6. Its electrochemical properties, including the influence of different scan rates, ions, and K~+ concentrations on the film, were studied. The membrane was characterized by IR and XPS. In IR spectrum, the vibration of cyano group verified from the formation of the film on the electrode. In XPS spectrum, the splitting of Fe2p_(1/2) )and Fe2p_(3/2)) showed that the valence of iron has been changed in the film formation, and a proper electropolymerization mechanism was put forward. The results showed the PrHCF film have some electrocatalytic activity to the oxidation of cysteine. The detection conditions for cysteine such as the potential and pH were also discussed.
ABSTRACT
Vitamin B1 self-assembled monolayer modified electrode (VB1-Au/SAMs/CME) was prepared and its electrochemical behavior was studied by cyclic voltammetry. The results showed that a self-assembled monolayer (SAM) was formed on the surface of gold electrode. \3-/4-redox couple was used as the electrochemical probe to study the electrochemical characteristics of SAM modified gold electrode and the results indicated that the existence of Vitamin B1 membrane on gold surface hindered the electron transfer. The electrochemical behaviors of dopamine(DA) and uric acid (UA) were investigated at VB1-Au/SAMs/CME. The results showed that the electrochemical oxidation of DA and UA could be electrocatalyzed. There were linear relationships between the anodic peak current and the concentration of DA(8.0×10-6-4.0×10-4 mol/L) and UA (6.0×10-5-2.2×10-4mol/L) respectively in differential pulse voltammograms. This modified electrode was effective to detect DA and UA in simultaneous determination of these species in a mixture.
ABSTRACT
The electrochemical behaviors of parathion(PT) on nano-Al2O3 film modified electrode(nano-Al2O3/GCE/CME) were investigated. It was found that the redox peak currents of PT remarkably increased and the oxidation peak potential negatively shifted at the nano-Al2O3/GCE/CME. All the experimental parameters were optimized and a simple and sensitive electroanalytical method was developed for the determination of PT. The oxidation peak current was linear with the concentration of PT over the range from 2.5×10-9 to 1.0×10-7 mol/L and 1.0×10-7 to 1.0×10-5 mol/L. A low detection limit of 1.0×10-9 mol/L was obtained for 30 s accumulation at open circuit(S/N=3). The relative standard deviation(n=10) was 3.8% for 1×10-5 mol/L PT. The proposed method was used for the quantitative analysis of PT in some vegetables and the results were satisfactory.