JOURNAL OF APPLIED CHEMISTRY
Year:2016 | Volume:11 | Issue:40|Papers Count:12

The electrocatalytic oxidation of captopril (CAP) has been studied by acetylferrocene (AF) modified NiO/NPs carbon paste electrode (AF/NiO/NPs/CPE). Cyclic voltammetry (CV), square wave voltammetry (SWV) and chronoamperometry were used to investigate the suitability of AF as a mediator for the electrocatalytic oxidation of CAP in aqueous solution. The catalytic reaction rate constant, kh was calculated (2.539×103 M-1 s-1) using chronoamperometry. The square wave voltammetric (SWV) peak currents of the electrode increased linearly with the corresponding CAP concentration in the range of 0.3-450 mM with a detection limit of 0.09 mM. The proposed sensor was used for determination of captopril in tablet and urine samples.

In the present investigation, HOMO-LUMO energy gap, polarizability, structural parameters, molecular mass, hardness, chemical potential and electrophilicity index of the trans-cinnamaldehyde as one of the active ingredients of cinnamon in the gas phase and in ethanol, acetone and dichloromethane solvents were calculated. Density Functional Theory calculations were performed by the B3LYP method with 6-311G+(d,p) and DGDZVP basis sets on the compounds. According to the calculations, HOMO-LUMO energy gap and hardness in the gas phase was the largest and in ethanol was the smallest, polarizability, softness, dipole moment, electrophilicity had the largest amount in ethanol and the smallest in the gas phase, chemical potential of compound in dichloromethane was the greatest and in the gas was the lowest.

Due to the many uses of copper metal and its alloys, great deal attention has done to different methods of corrosion protection in corrosive environments. Using of organic coating is a great way to protect metal from corrosion, especially if the coating also has good mechanical properties. Electrodeposit of conductive polymer on the surface of an electrode is a very wide research in electrochemistry during the last decades. In this research, homogeneous and the adherent polyaniline coating was electrosynthesized on copper metal by using the chronopotentiometery under galvanostatic conditions method. During the formation of polyaniline coatings, three stages (electro-adsorption of monomer and electrolyte and initiation of formation of passive film, growth and impingement of the passive film and decomposition of the latter and formation of polymer coatings) are observed. The synthesized coatings were characterized by Fourier transform infrared spectroscopy (FT-IR), UV-Vis spectroscopy and SEM. The improved corrosion protection effect of polyaniline after 24 hours immersion time in 3.5% NaCl solution was demonstrated by performing a series of electrochemical experiments potentiodynamic and impedance measurements on copper electrode. The effect of applied current density on the protective properties of polyaniline coatings has been investigated, and it was shown that protection efficiency depends on the applied current density. The corrosion current decreases significantly from 43.56 mA cm-2 for blank electrode copper to 0.84 mA cm-2 for the copper that was coated with polyaniline under the same conditions. According to the results, the polyaniline coating enhanced the corrosion protection effect compared to uncoated electrode.

Prevention, recognize and treatment of cancer is one target and concern in medical science. Novel drug delivery systems have been provided In order to improve the treatment of cancer. In these systems, specified amount of the drug with an appropriate carrier is forwarded inside the cell. Nanotubes can be used as a carrier for drug delivery due to the large empty space inside nanotubes for encapsulation the drug. With regard to the importance of drug delivery in cancer therapy, In this paper two types of Armchair (1 0,10) and Zigzag ( 18,0) single-walled carbon nanotubes and the method of encapsulation the Gemcitabine anti-cancer drug were checked out. The drug is stable energetically in both nanotubes due to the energy absorption of the drug in nanotubes. According to achieved Center of mass (COM) and Root-mean-square displacement (RMSD) diagrams, Zigzag carbon nanotube can be a suitable carrier to encapsulate the Gemcitabine anti-cancer drug.

In this work conventional Uv-Vis spectroscopy was used for trace analysis of Dysprosium (III). In order to improve selectivity and detection limit of method, ultrasound-assisted dispersive liquid-liquid micro-extraction (DLLME) was applied for extraction of Dy(III) from aqueous sample. The method was based on the formation of Dy (III)-alpha-benzoin oxime complex and its extraction in to chloroform using a DLLME technique. It was found that the crucial factor for the complex formation is an alkaline alcoholic medium. The effective parameters on the separation and determination process such as pH, ligand concentration, amount and type of dispersive, and extracting solvent were investigated and optimized. Under the optimized conditions, the calibration graph was linear in the ranges of 6.1×10-7-6.8×10-4mol L-1 with the detection limit of 3×10-7mol L-1. The pre-concentration of 20mL of sample gave enhancement factor of 70. The proposed method was applied for determination of Dy(III) ion in spiked urine and water samples.

In recent years, many efforts have been done to provide biological platforms for enzyme immobilization, biotechnology applications and biosensor developments. One of these platforms is cysteine amino acid. Much cysteine immobilization on the electrode surface, causing larger amount of protein loaded on the electrode surface which improves the biosensor’s operation. In the present study cysteine was fixed on bare glassy carbon electrode and glassy carbon electrode modified graphene or graphene oxide by electrochemical method. Cyclic voltammetry showed the best cysteine immobilization was on the glassy carbon electrode modified graphene. In addition, the use of cysteine-graphene nanocomposit on the glassy carbon electrode surface not only loading a larger amount of glucose oxidase enzyme on the surface of the modified electrode, but also providing the graphene as a good platform for facilitating electron transfer from the electrode to the redox enzyme

In this study, cobalt hydroxide nanoplates were prepared from nitrate bath by electrochemical deposition method. Electrodeposition experiments were performed at a current density of 0.5 mA cm-2 in RT condition. The structure and morphology of the prepared sample were investigated via XRD, FT-IR, SEM and TEM analyses. The structural analyses by XRD and IR showed that the prepared deposit has pure b phase of Co (OH)2. Also, SEM and TEM observations revealed that the prepared sample has hexagonal plate-like morphology at nano-scale. The edge lengths of the plates range from 100 to 200 nm. The supercapacitive behavior of the prepared nanoplates was evaluated by cyclic voltammetry (CV) and charge-discharge tests. For this purpose, CV and charge-discharge tests of the electrode prepared from hydroxide nanoplates were conducted in the potential window of -0.2-0.55 V vs. Ag/AgCl at 1M KOH electrolyte. For first cycle of charge-discharge, the capacity as high as 915.5 F g-1 was measured which is in agreement with the values calculated form CV curves. Also, the capacity of 894.7 F g-1 was calculated for the 500th cycle, which only 2% capacity decay. These results confirmed that the b-Co(OH)2 nanoplates have excellent supercapacitive behavior and high cycle life, which can be a promising candidate for the electrochemical supercapacitors.

A simple and efficient method has been presented for the synthesis of 3, 4, 5-substituted furan-2-one derivatives. One-pot three-component reaction of aromatic amines, aromatic aldehydes and dialkyl acetylenedicarboxylates in the presence of oxalic acid dihydrate in ethanol as a green solvent leads to furan-2-one dreviatives. Some of the advantages of this procedure are mild conditions, high atom economy inexpensive catalyst and high yields. Moreover, the products were obtained through simple filtering and no need to column chromatography.

In this article, nano-NiO as a heterogenuos and recyclable catalyst has been used for the synthesis of 1H-Pyrazolo [1,2-b]Phthalazine-5,10-Diones by the reaction of malononitrile, aldehydes and phthalhydrazide under solvent-free conditions. Short reaction time, reusability easy work up and high yields of products are the advantages of this procedure.

The purpose of this research is preparation of titanium dioxide nanotubes modified with nickel nanoparticles as a photocatalyst sensitive to visible light. For this purpose, at first, titanium dioxide nanotubes was synthesized on the surface of titanium using electrochemical anodizing; then by immersion of prepared nanotubes in an aqueous solution of nickel nitrate, film of nickel nanoparticles on the surface of the nanotubes were produced. Morphology and crystal structure of the resulting films were studied using scanning electron microscopy and X-ray diffraction. To determine the composition and confirmation the presence of nickel nanoparticles, we used from energy dispersive X-ray spectroscopy (EDX). Then, photocatalysts efficiency of obtained nano-catalysts for the removal of methylene blue dye was performed. Photocatalytic test results showed that produced nanocatalysts have good activity.

This article examines a simple and efficient method for extraction and preconcentration at the same time very low values of organochlorine (OCPS) in the river water samples, based on the specific situation of dispersive liquid-liquid microextraction in a long thin tube. The effect of influencing factors in microextraction such as the type and volume of solvents dispersive and extracted and volume of sample aqueous solution was studied and optimized. In the optimized qualification, mixture of 2.5 ml acetone and 0.5 ml n-hexane and toluene (1:1) for 30 seconds to 19 ml water solution is injected into the pipe and formed cloudy solution and toxins transferred to the organic phase and reached the top of the column. Finally, after extraction and cleanup 1 ul of samples injected into gas chromatography flame ionization and compared to standard solutions curve, were determined. Under optimal conditions, the linear range of calibration curves in the range of 0.6 to 1.4 ug/ml and relative recovery of 93.1 to 98.6, relative standard deviation much lower than 5.9% and correlation coefficient of 0.95 was calculated. The limit of detection and quantification limits, respectively, in the range of 0.8 to 1.3 and 3.1 to 3.7 ug/l respectively. The advantage of this method is the simplicity, speed, low cost and high recovery percentage.

In this study, a magnetic nanocomposite based on amino-functionalized magnetic nanoparticles (Fe3O4-NH2) is synthesized by Grafting and Solvothermal methods. This nanocomposite is used as an adsorbent for the removal of Pb(II) ion from wastewater. Then, X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) techniques are implemented for investigations of structural changes of synthesized magnetic nanocomposite. Moreover, response surface methodology (RSM) is applied to obtain an optimal response of the interactions between the most important parameters in removal of Pb(II) by using Fe3O4-NH2. Experimental results demonstrated that the maximum adsorption capacity and removal efficiency in optimal conditions, such as the (initial concentration Pb(II) (187 mg/g), temperature (40oC), adsorbent dosage (1.5 g/l) and pH=4.9) obtained (133.43 mg/g) and (96%) respectively. According to the thermodynamic parameters ΔH and ΔG, adsorption process was spontaneous and endothermic. In addition, the experimental data are analyzed by using the Langmuir and Freundlich isotherm models and the maximal equilibrium uptake capacity is obtained 169.5 mg/g. Finally, kinetic studies showed that the equilibrium time occurred at 90 minutes and the adsorption process by a good agreement with the second-order kinetic model with the highest values of R2 and K2=4.9 (g/mg min). This study showed that a magnetic nanocomposite based on Fe3O4-NH2 can be employed as an efficient adsorbent for the removal of Pb(II) from contaminated water sources.