Glassy carbon electrode modified by Poly (m-aminobenzoic acid) /nano SiO2 film and electrical and electrochemical properties

Poly(m-aminobenzoic acid) (m-ABA) film is deposited on glassy-carbon electrode (GCE) by electropolymerization in pH 7.0 phosphate buffer solutions (PBS). The electrochemical behavior of polymer film obtained is characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) studies. In the present study, the effect of the scan rate on the current peak is investigated in the range of 50-200 mV/sec and, it is observed that the anodic and cathodic peak all increased with the solution pH until it reached 8 and then decreased until 11. In addition, a new electrode is developing by electrodeposition of SiO2 nanoparticles on glassy-carbon electrode. The electrochemical behavior of polymer at the nanoparticles SiO2/GCE is investigated. Electrical properties as a function of frequency and temperature have also indicated a great interaction between epoxy matrix and different poly (m-aminobenzoic acid) / SiO2 by physical mixing procedure

Glassy carbon electrode modified by Poly (m-aminobenzoic acid) /nano SiO2 film and electrical and electrochemical properties

Poly(m-aminobenzoic acid) (m-ABA) film is deposited on glassy-carbon electrode (GCE) by electropolymerization in pH 7.0 phosphate buffer solutions (PBS). The electrochemical behavior of polymer film obtained is characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) studies. In the present study, the effect of the scan rate on the current peak is investigated in the range of 50-200 mV/sec and, it is observed that the anodic and cathodic peak all increased with the solution pH until it reached 8 and then decreased until 11. In addition, a new electrode is developing by electrodeposition of SiO2 nanoparticles on glassy-carbon electrode. The electrochemical behavior of polymer at the nanoparticles SiO2/GCE is investigated. Electrical properties as a function of frequency and temperature have also indicated a great interaction between epoxy matrix and different poly (m-aminobenzoic acid) / SiO2 by physical mixing procedure

Theoretically nanoscale study on ionization of muscimol nano drug in aqueous solution

In the present work, acid dissociation constant (pKa) values of muscimol derivatives were calculated using the Density Functional Theory (DFT) method. In this regard, free energy values of neutral, protonated and deprotonated species of muscimol were calculated in water at the B3LYP/6-31G(d) basis sets. The hydrogen bond formation of all species had been analyzed using the Tomasi's method. It was revealed that the theoretically calculated pKa values were in a good agreement with the existing experimental pKa values, which were determined from capillary electrophoresis, potentiometric titration and UV-visible spectrophotometric measurements.No presente trabalho, calculou-se a constante de dissociação do ácido (pKa) dos derivados de muscimol, utilizando-se o método da teoria do funcional de densidade (DFT). Com esse objetivo, calcularam-se os valores das espécies neutra, protonada e desprotonada do muscimol em água em base B3LYP/6-31G(d). A formação da ligação de hidrogênio de todas as espécies foi analisada utilizando o método de Tomasi. Demonstrou-se que os valores de pKa calculados teoricamente estavam em boa concordância com os valores experimentais disponíveis, determinados por eletroforese capilar, titulação potenciométrica e medidas por espectrofotometria UV-visível

Electrolyte and solvent effects on voltammetry behavior and surface morphology of Polypyrrole films deposited on glassy carbon electrode in the redox process

Polypyrrole (PPy) films were electrochemically synthesized on glassy carbon electrode in different electrolytes and solvent media. Voltammetry studies of PPy films doped with Cl−, ClO4−, NO3− anions showed that the redox activity of the polymer is affected by the nature of the anions and solvent used in the electrochemical synthesis. The mobilities of the anions exhibited a well-defined order: ClO4− < Cl− < NO3−. The electrodeposited PPy films were characterized ex situ independently by atomic force microscopy (AFM) technique. The effect of solvent on the surface morphology of PPy films was clarified by AFM imaging. Our results showed that the level of doping will depend on the polarity of the solvent used. In polar solvent like DMSO, the doping of Cl− anion is predominant. The results obtained suggested the presence of chemisorbed anions on the surface of PPy films

Theoretically nanoscale study on ionization of muscimol nano drug in aqueous solution

In the present work, acid dissociation constant (pKa) values of muscimol derivatives were calculated using the Density Functional Theory (DFT) method. In this regard, free energy values of neutral, protonated and deprotonated species of muscimol were calculated in water at the B3LYP/6-31G(d) basis sets. The hydrogen bond formation of all species had been analyzed using the Tomasi's method. It was revealed that the theoretically calculated pKa values were in a good agreement with the existing experimental pKa values, which were determined from capillary electrophoresis, potentiometric titration and UV-visible spectrophotometric measurements

Thermodynamic study of asparagine and glycyl-asparagine using computational methods

This work aimed to develop an ab initio procedure for accurately calculating pKa values and applied it to study the acidity of asparagine and glycyl-asparagine. DFT methods with B3LYP composed by 6-31+G(d) basis set were applied for calculating the acidic dissociation constant of asparagine and glycyl-asparagine. The formation of intermolecular hydrogen bonds between the available species and water was analyzed using Tomasi,s method. Results showed that in alkaline solutions, the cation, anion and neutral species of asparagine and glycyl-asparagine were solvated with one, two, three and four molecules of water, respectively. There was an excellent similarity between the experimentally attained pKavalues and the theoretically ones in this work

Electrochemical Study of Complex Formation of Cerium (IV) Ion with Glycyl-Glycine and Glycyl-Valine

Biochemical parameters are indicators measured in a biological system which can be related to exposure to, or effects of, a contaminant compound. In current study some serum biochemical parameters were measured in order to investigate patterns of response and change caused by the mercury contamination in yellowfin sea bream. According to the LC50, five mercury treatment was selected. Serum glucose was measured photometrically based on the quantification of NADH after a glucose oxidation catalyzed by glucose dehydrogenase. Serum total protein levels were determined with bovine serum albumin serving as standard. Values recorded for activity of total protein show high significance depletion (P<0.001) with mercury exposed. Although glucose was increase in different treatment, but there was not find significant variation. Results of the present investigation indicated that the sub- acute mercury concentrations tested is a toxic substance in yellowfin sea bream and may cause several changes in the serum biochemical parameters

Theoretically nanoscale study on ionization of muscimol nano drug in aqueous solution

In the present work, acid dissociation constant (pKa) values of muscimol derivatives were calculated using the Density Functional Theory (DFT) method. In this regard, free energy values of neutral, protonated and deprotonated species of muscimol were calculated in water at the B3LYP/6-31G(d) basis sets. The hydrogen bond formation of all species had been analyzed using the Tomasi's method. It was revealed that the theoretically calculated pKa values were in a good agreement with the existing experimental pKa values, which were determined from capillary electrophoresis, potentiometric titration and UV-visible spectrophotometric measurements

<i>Ab initio</i> and DFT studies on ionization of octopamine and 6-aminopenicillanic acid in aqueous solution

619-626The existing quantum chemical methods to accurately predict pKa and to determine the trade-off between accuracy and computational cost have been evaluated by ab initio and density functional theory with the B3LYP functional and 6-31+G(d) basis sets and polarizable continuum solvation model. The calculated free energies for determination of pKa values, and intermolecular hydrogen bonds in aqueous solutions of octopamine and 6-aminopenicillanic acid have been computed. This study shows that there is reasonable agreement between the theoretically calculated pKa values and the experimentally determined pKa values for the acid-base reactions obtained by potentiometric and spectrophotometric methods reported in the literature