This work reports the catalytic activity of a polymer electrogenerated from Fe(III)-5-amino-1,10-phenantroline solution at a carbon nanotubes paste electrode (CNTPE) towards the oxidation and mainly the reduction of hydrogen peroxide. The important role of carbon nanotubes on the generation of poly(Fe(III)-5-amino-1,10-phenantroline) is demonstrated through the comparison with the behavior of graphite paste electrode (CPE). The polymer electrogenerated at CNTPE largely improves the amperometric detection of hydrogen peroxide at À 0.100 V. The analytical application of the resulting electrode is demonstrated in connection with the design of a glucose biosensor based on the deposition of GOx and diluted Nafion on the top of the polymer-modified CNTPE. The quantification of glucose in human serum samples showed a good correlation with the values obtained by the spectrophotometric technique.
This work reports the advantages of using glassy carbon electrodes modified with multiwall carbon nanotubes (MWCNT) dispersed in polyethylenimine (PEI). The presence of MWCNTs wrapped by PEI largely facilitated the strong adsorption of uric acid (UA) and allowed its highly sensitive and selective quantification even in the presence of high excess of ascorbic acid. The selected conditions for the electrochemical sensing were 5 s accumulation at −0.300 V under stirring and quantification in a 0.050 M phosphate buffer solution pH 7.40 by differential pulse voltammetry adsorptive‐stripping after medium exchange. The platform allowed the successful application in the quantification of UA in urine.
In this work, the results related to the electrochemical behavior of the Fe (III)-5-Amino 1,10 phenanthroline system (Fe(III)-5-Aphen) are presented. The electropolymerization process of this chemical species was studied onto a carbon paste electrode (CPE), as a function of pH's values inside the 0.3 -6.2 interval. The cyclic voltammetry technique was used to form and determine the incorporation of the Fe (III) ion into the polymer matrix. It was observed that Fe(III) was incorporated into de polymer matrix in the 2.5 < pH > 6.0 interval. At pH < 2.5, only the characteristic electrochemical signals of the 5-Aphen ligand were observed. These results are in good agreement with the spectrophotometric study of the Fe (III)-5-Aphen complex in aqueous solution. In these experiments, it was found that the metal complex is stable at pH > 2.5 and poly Fe (III)-5-Aphen films are obtained.
In this work the formation and morphologycal characteristics of the films formed on two carbon substrates were studied by electrochemical and spectrophotometric techniques. The two carbon substrates were modified with a complex aqueous solution 2.5x10-4M Fe (III) 5-Amino-1,10 phenanthroline (Fe (III)-5-Aphen) with 1:3 stoichiometry] at pH =6. The Poly Fe(III)-5-Aphen films, were characterized using electrochemical techniques like cyclic voltammetery (CV) and spectroscopic techniques.
In this work, the results obtained by using a composite (dispersing multiple- wall carbon nanotubes in mineral oil) (CNTPE) and modified with a polymeric matrix of poly Fe (III)-5-amino 1,10 phenanthroline (MCNTPE) thus to develop a sensor for quantifying hydrogen peroxide based on the polymer electrocatalytic effects are presented. By means of hydrodynamic voltamperometry, it was possible to determine the ox-red potentials of hydrogen peroxide by using the MCNTPE. The amperometric response to H2O2 by using the CNTPE and MCNTPE was evaluated at -0,100 and 0,700 V vs Ag/AgCl. At -0,100 V, the sensibility of the MCNTPE was increased by a factor of 200 in comparison with the CNTPE. At 700 mV, the sensibility of the MCNTPE was increased by a factor of 268 respected to the CNTPE one. These results show that a new composite with electrocatalytic properties can be proposed to develop electrochemical sensors for the quantification of hydrogen peroxide.
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