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Papers by juan armijo

Research paper thumbnail of Electro-oxidation of 1-amino-9,10-anthraquinone and O-phenylenediamine and the Influence of Its Copolymerizaton in the Modified Electrode Properties

Electrochemistry, 2013

Poly(1-amino-9,10-anthraquinone-coo -phenylenediamine) (P1AAQ-co-POPD) was synthesized by electro... more Poly(1-amino-9,10-anthraquinone-coo -phenylenediamine) (P1AAQ-co-POPD) was synthesized by electrochemical methods on stainless steel electrodes (SS) using equal monomer concentration in acetonitrile/acidified water mixture as solvent. Electrochemical characterization allows, among others, determining the characteristic redox couple potential of the quinone group, which is one of the advantages of having achieved the copolymerization. FT-Raman, ATR and UV-Vis characterization confirms the formation of the copolymer, particularly, by the occurrence of a novel signal ascribed to a new C-N type bond. Besides, the conductivity of the deposits was determined, which enabled the conducting properties of the products to be verified. The topographical and morphological characterization accomplished by atomic force (AFM) and transmission electron (TEM) microscopy showed how the inclusion of o-phenylenediamine (OPD) increases the homogeneity of the copolymer, which in turn enables designing likely applications of the electrode modified with this novel polymeric material.

Research paper thumbnail of Electrochemistry of methimazole on fluorine-doped tin oxide electrodes and its square-wave voltammetric determination in pharmaceutical formulations

Electrochimica Acta, 2013

The electrochemical behavior of methimazole (MTZ) at fluorine-doped tin oxide electrodes has been... more The electrochemical behavior of methimazole (MTZ) at fluorine-doped tin oxide electrodes has been studied by cyclic (CV) and square wave (SWV) voltammetric techniques. The CV studies were performed in a wide range of potential scan rates and pHs. The results showed an irreversible, diffusion controlled process for the electrochemical reaction of MTZ. Under the optimum conditions SVW measurements showed that a linear relationship between MTZ anodic peak current vs. concentration exists in the range 6 × 10 −6-240 × 10 −6 mol L −1 using buffer at pH 3.0. A 1.98 × 10 −6 mol L −1 detection limit, relative standard deviation (RSD) below 2.0% and good sensitivity was obtained. Therefore these electrodes are promising candidates for the reliable electrochemical determination of MTZ in pharmaceutical preparations with good selectivity and suitable recovery.

Research paper thumbnail of Electro-oxidation of 1-amino-9,10-anthraquinone and O-phenylenediamine and the Influence of Its Copolymerizaton in the Modified Electrode Properties

Electrochemistry, 2013

Poly(1-amino-9,10-anthraquinone-coo -phenylenediamine) (P1AAQ-co-POPD) was synthesized by electro... more Poly(1-amino-9,10-anthraquinone-coo -phenylenediamine) (P1AAQ-co-POPD) was synthesized by electrochemical methods on stainless steel electrodes (SS) using equal monomer concentration in acetonitrile/acidified water mixture as solvent. Electrochemical characterization allows, among others, determining the characteristic redox couple potential of the quinone group, which is one of the advantages of having achieved the copolymerization. FT-Raman, ATR and UV-Vis characterization confirms the formation of the copolymer, particularly, by the occurrence of a novel signal ascribed to a new C-N type bond. Besides, the conductivity of the deposits was determined, which enabled the conducting properties of the products to be verified. The topographical and morphological characterization accomplished by atomic force (AFM) and transmission electron (TEM) microscopy showed how the inclusion of o-phenylenediamine (OPD) increases the homogeneity of the copolymer, which in turn enables designing likely applications of the electrode modified with this novel polymeric material.

Research paper thumbnail of Electrochemistry of methimazole on fluorine-doped tin oxide electrodes and its square-wave voltammetric determination in pharmaceutical formulations

Electrochimica Acta, 2013

The electrochemical behavior of methimazole (MTZ) at fluorine-doped tin oxide electrodes has been... more The electrochemical behavior of methimazole (MTZ) at fluorine-doped tin oxide electrodes has been studied by cyclic (CV) and square wave (SWV) voltammetric techniques. The CV studies were performed in a wide range of potential scan rates and pHs. The results showed an irreversible, diffusion controlled process for the electrochemical reaction of MTZ. Under the optimum conditions SVW measurements showed that a linear relationship between MTZ anodic peak current vs. concentration exists in the range 6 × 10 −6-240 × 10 −6 mol L −1 using buffer at pH 3.0. A 1.98 × 10 −6 mol L −1 detection limit, relative standard deviation (RSD) below 2.0% and good sensitivity was obtained. Therefore these electrodes are promising candidates for the reliable electrochemical determination of MTZ in pharmaceutical preparations with good selectivity and suitable recovery.

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