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Mohadesi A.,Payame Noor University | Teimoori E.,Payame Noor University | Taher M.A.,Shahid Bahonar University of Kerman | Beitollah H.,Islamic Azad University at Zarand
International Journal of Electrochemical Science | Year: 2011

Traces of cobalt (II) can be determined by adsorptive stripping voltammetry using Nitroso-S as complex forming reagent. First in acetate buffer pH 5.0, cobalt (II)-Nitroso-S complex was adsorbed on the carbon paste electrode with an accumulation potential of +0.1 V. Following this, adsorbed complex was detected by cathodic differential pulse voltammetric scan from +0.1 to -0.6 V. The effective parameters in sensor response were examined. The detection limit of Co(II) was 1.8 μg l-1 and relative standard deviations for 10 and 100 μg l-1 of Co(II) were 0.8 and 1.2%, respectively. The calibration curve was linear for 3.3-187.1 μg l-1 Co(II). This technique does not use mercury and therefore, has a positive environmental benefit. The method, which is reasonably sensitive and selective, has been successfully applied to the determination of trace amount of Co(II) in water samples. © 2011 by ESG.

Yaghoubian H.,Islamic Azad University | Beitollah H.,Islamic Azad University at Zarand | Soltani-Nejad V.,Islamic Azad University at North Tehran | Mohadesi A.,Payame Noor University | And 3 more authors.
International Journal of Electrochemical Science | Year: 2011

A carbon paste electrode (CPE) modified with ferrocenedicarboxylic acid (FCD) and carbon nanotubes (CNTs), was prepared for determination of epinephrine (EP) in the presence of acetaminophen (AC). The electrochemical response characteristics of the modified electrode toward EP and AC were investigated by differential pulse voltammetry (DPV). The results showed an efficient catalytic role for the electro-oxidation of EP and AC, leading to a remarkable peak resolution (~250 mV) for two compounds. Under the optimum conditions, the calibration curve for EP was obtained in the range of 5.0×10-8 to 4.5×10-4 M. The proposed method was applied to determination of EP and AC in real samples and the obtained results were satisfactory. © 2011 by ESG.

Fouladgar M.,Islamic Azad University at Falavarjan | Hadjmohammadi M.R.,University of Mazandaran | Khalilzadeh M.A.,Islamic Azad University at Qaemshahr | Biparva P.,University of Mazandaran | And 2 more authors.
International Journal of Electrochemical Science | Year: 2011

A sensitive and selective electrochemical method for the determination of amoxicillin (AMX) was developed using a ferrocenedicarboxylic acid modified carbon natubes paste electrode (FDCCNTPE). The modified electrode exhibited good electrocatalytic activity for electrochemical oxidation of amoxicillin at the pH of 10.5 phosphate buffer solution. The diffusion coefficient (D= 4.62 ×10-5 cm2 s-1), and the kinetic parameter such as the electron transfer coefficient (α= 0.494) of AMX at the surface of FDCCNTPE were determined using electrochemical approaches. Under the optimized conditions, the electrocatalytic oxidation peak current of amoxicillin showed two linear dynamic ranges with a detection limit of 8.7 nmol L-1), amoxicillin. The linear calibration ranges was in the range of 0.03-0.35 μmol L-1 and 0.50-32.70 μmol L-1), amoxicillin using square wave voltammetric method. Finally, this modified electrode was also examined for the determination of amoxicillin in real samples such as drug and urine. © 2011 by ESG.

Afzali D.,Research Institute of Environmental science | Mostafavi A.,Shahid Bahonar University of Kerman | Beitollah H.,Islamic Azad University at Zarand
Microchimica Acta | Year: 2010

An organo-nanoclay is used as a new, easily accessible, and stable solid sorbent for the preconcentration of trace amounts of rhodium ions from aqueous solution, this followed by its determination by flame atomic absorption spectrometry (FAAS). Rh(III) ion was first complexed with 2,3,5,6-tetra(2-pyridyl) pyrazine (TPPZ) at pH values between 3.0 and 4.7, and then the complex was then adsorbed onto the nanoclay. The rhodium ions were eluted from the sorbent with HCl. The rhodium in the effluent was determined by FAAS. The linear analytical range is between 0.14 ng mL -1 and 20.0 μg mL -1 in the initial solution, the relative standard deviation at 2.0 μg mL -1 of rhodium is 2.6% (n=8), the detection limit is 0.03 ng mL -1, and the preconcentration factor is 140. Experimental parameters including the pH, eluent type, interference by other ions and breakthrough volume were optimized. The method was applied to the determination of rhodium in water, road dust and synthetic samples. © 2010 Springer-Verlag.

Rezaeian A.,Islamic Azad University at Abarkouh | Rasa I.,Shahid Beheshti University | Amiri A.,Islamic Azad University at Zarand | Jafari M.R.,Islamic Azad University at Tehran
Arabian Journal of Geosciences | Year: 2014

The study of oxygen and carbon isotopic ratios has gained importance to determine the origin of ore-bearing fluids, carbon origin, and also to determine the formation temperature of non-sulfide Pb and Zn minerals. In order to determine the origin of fluids and carbon existing in Zn carbonate minerals in Chah-Talkh deposit, initially the amounts of δ18OSMOW and δ13CPDB changes in various zinc minerals in important deposits in Iran and the world were studied, and then by comparing these values in Chah-Talkh deposit with those of other deposits, the origin of fluids responsible for ore forming, carbon, and formation temperature of Chah-Talkh deposit was determined. The range of δ18OSMOW changes in smithsonite mineral in non-sulfide lead and zinc deposits varies from 18.3 to 31.6 ‰, and δ18OSMOW in hydrozincite mineral varies from 7.8 to 27 ‰. Due to the impossibility of smithsonite sampling from Chah-Talkh deposit (due to it being fine-grained and dispersed), hydrozincite minerals which have high isotopic similarities with smithsonite are used for the isotopic analysis of carbon and oxygen. The range of δ18OSMOW changes in hydrozincite mineral of Chah-Talkh deposit varies from 7.8 to 15.15 ‰, which places in the domain of metamorphic water. The extensiveness of δ18OSMOW changes in Chah-Talkh indicates the role of at least two fluids in the formation of non-sulfide minerals. The obtained formation temperature of non-sulfide minerals (hydrozincite) in Chah-Talkh deposit is 70 to 100 °C, which indicates the role of metamorphic fluids in the formation of deposit. Complete weathering of sulfide minerals to a depth of 134 m confirms the role of rising metamorphic fluids in the formation of non-sulfide minerals. The δ13CPDB values of Chah-Talkh deposit are set in the range of atmospheric CO2 and carbonate rocks, in which the existence of atmospheric CO2 indicates the role of atmospheric fluids, and the existence of carbonate carbon rock indicates of the role of metamorphic fluids in the precipitation of non-sulfide Zn minerals. © 2013 Saudi Society for Geosciences.

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