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Babaei A.,Arak University | Yousefi A.,Arak University | Afrasiabi M.,Arak University | Shabanian M.,Standard Research Institute SRI
Journal of Electroanalytical Chemistry | Year: 2015

A novel chemically modified electrode is constructed based on a multiwalled carbon nanotubes, nickel(II) hydroxide nanoparticles and MCM-41 molecular sieve composite modified glassy carbon electrode. It is demonstrated that the sensor can be used for the simultaneous determination of dopamine (DA), acetaminophen (ACT) and indomethacin (INDO). The measurements were carried out by the application of differential pulse voltammetry (DPV), cyclic voltammetry (CV) and chronoamperometry (CA). Under the optimum conditions the modified electrode provides a linear response versus DA concentrations in the range of 1.5-45 μM and 70-350 μM, ACT concentrations in the range of 0.2-20 μM and 20-220 μM and INDO concentrations in the range of 0.8-40 μM and 60-160 μM, respectively using the differential pulse voltammetry method. The modified electrode was used for determination of DA, ACT and INDO in real samples with satisfactory results. © 2015 Elsevier B.V. All rights reserved.

Khalili D.,Shiraz University | Banazadeh A.R.,Standard Research Institute SRI
Bulletin of the Chemical Society of Japan | Year: 2015

An efficient chemical method for the synthesis of benzimidazoles, benzothiazoles, and benzoxazoles has been developed through the condensation of various aldehydes with o-phenylenediamine, o-aminothiophenol, and o-aminophenol using graphene oxide (GO) as an oxidant in water. These benzazoles are also prepared through a one-pot oxidation/condensation tandem process by reacting alcohols with 2-amino-(thio)phenol/aniline in the presence of GO in poly(ethylene glycol) as a safe media. Moreover, this carbonaceous material could be readily separated using a simple filtration. © 2015 The Chemical Society of Japan.

A green, convenient and efficient procedure is reported for the synthesis of S-aryl dithiocarbamates by a simple one-pot three component Ullmann-type condensation of an amine, carbon disulfide and an aryl iodide. Magnetically separable and reusable copper oxide (Fe3O4-CuO) nanoparticles are used as a heterogeneous catalyst under base- and solvent-free conditions. Nanoparticles with an average size of 10-20 nm has been successfully prepared by a simple precipitation method in aqueous medium from readily available inexpensive starting materials. The catalyst could be easily separated from the reaction mixture by using an external magnet and recycled four times without significant loss in its activity. © 2016 The Royal Society of Chemistry.

Hafezi B.,Standard Research Institute SRI | Majidi M.R.,University of Tabriz
Analytical Methods | Year: 2013

A fast, sensitive and accurate electrochemical sensor based on copper nanostructures for electrocatalytic determination of nitrate has been developed. Cyclic voltammetry and hydrodynamic amperometry were employed to characterize the response of the sensor to nitrate that changes linearly in the concentration range from 1 to 35 μM. The repeatability of measurements for nitrate was evaluated as 2.3% (N = 15) and the limit of detection of the method was found to be 0.59 μM (S/N = 3). The content of nitrate in foodstuffs and mineral water samples was determined by the proposed and the reference method based on Griess protocol at the 95% confidence level. No interferences were observed from nitrite ions on the nitrate analysis. The interference from chloride ions was also examined. © 2013 The Royal Society of Chemistry.

Shabanian M.,Standard Research Institute SRI | Basaki N.,Islamic Azad University | Khonakdar H.A.,Iran Polymer And Petrochemical Institute | Jafari S.H.,University of Tehran | And 2 more authors.
Applied Clay Science | Year: 2014

New long aliphatic chain polyamide/Mg-Al layered double hydroxide (LDH) nanocomposites were successfully prepared via a solution intercalation technique under ambient condition in N,N-dimethylacetamide as solvent. The polyamide was synthesized using direct polycondensation reaction from an oleic acid based monomer which was characterized by proton nuclear magnetic resonance and size exclusion chromatography. The polyamide showed a semi-crystalline structure with melting temperature of 223. °C. Organo-modified Mg-Al LDH was produced by one-step method and used to improve properties of the polyamide. Thermal properties and flame retardancy of the nanocomposites were studied by thermogravimetric analysis, differential scanning calorimetry and microscale combustion calorimeter. The thermal degradation results in both air and nitrogen atmospheres showed that the addition of organo-modified LDH resulted in a substantial increase in the thermal stability and char yields of the nanocomposites as compared to the neat polyamide. The flammability tests revealed that incorporation of the organo-modified LDH in the polyamide resulted in a reduction of the heat release rate, heat release capacity and total heat release. © 2014 Elsevier B.V.

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