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Tehrān, Iran

Soltani N.,Shahrekord University | Haddadi H.,Shahrekord University | Asgari M.,NFCRS | Semnani A.,Shahrekord University
Journal of Radioanalytical and Nuclear Chemistry | Year: 2015

Thorium cannot be determined by direct polarography or conventional stripping voltammetry. Higher sensitivity has been achieved by square wave anodic stripping voltammetry of the thorium complex with oxine at a carbon paste electrode. In the pH at 1.0 the peak current of the complex was linearly dependent upon the concentration of Th(IV) within the range of 2.0 × 10−9–2.2 × 10−8 M, with the limit of detection 0.2 nM, the accumulation time, and the accumulation potential were 200 s and −0.6 V, respectively. © 2014, Akadémiai Kiadó, Budapest, Hungary. Source


Behzad M.,NFCRS | Asgari M.,NFCRS | Shamsipur M.,Razi University | Maragheha M.G.,NFCRS
Journal of the Electrochemical Society | Year: 2013

A glassy carbon electrode (GCE) modified with gold nanoparticles (GNPs) was used for the determination of sub-nanmolar amounts of mercury in water samples using differential pulse stripping voltammetry (DPSV) and electrochemical impedance spectroscopy (EIS). The GNPs/ GCE electrode revealed a significant improvement for mercury detection compared with the unmodified GCE. Under the optimized experimental conditions, the modified GNPs/GCE revealed broad linear ranges of 1 to 500 nM (LOD = 0.1 nM) and 10-50 pM (LOD = 0.05 pM) for DPSV and EIS, respectively. The limits of detections obtained are much below the corresponding guideline value from the World Health Organization (WHO). The proposed DPSV method was successfully applied to the analysis of mercury content of tap water samples. © 2013 The Electrochemical Society. Source


Haji Hosseini M.,NFCRS | Asaadi P.,Islamic Azad University at Saveh | Rezaee M.,NFCRS | Rezaei M.R.,Islamic Azad University at Saveh | And 3 more authors.
Chromatographia | Year: 2013

This work proposes a new, rapid and simple homogeneous liquid-liquid microextraction via flotation assistance technique for the analysis of six organochlorine pesticides in water samples. A special extraction cell was used to facilitate collection of the low-density solvent extract. No centrifugation was required in this procedure. Determination was carried using gas chromatography-mass spectrometry. The water sample solution was then added into the extraction cell containing appropriate mixture of extract and homogeneous solvents. In the first step, a homogeneous solution and then with the continuation of water sample injection, a cloudy solution was formed. Using air flotation, the organic solution was collected at the conical part of the designed cell. The optimized levels of effective parameters were found based on response surface methodology approach. Applying the optimized conditions to the system understudy, the limits of detection of all target analytes were obtained in the range of 1.4-7 ng mL-1, while the precisions were found to be in the range of 11.08-14.87 (RSD, n = 3). The linearity of the method lay in the range of 10-150 ng mL-1 with the coefficients of correlation (r 2 ) ranging from 0.998 to 0.999. © 2013 Springer-Verlag Berlin Heidelberg. Source


Behzad M.,NFCRS | Asgari M.,NFCRS | Taghizadeh M.,NFCRS | Maragheh M.G.,NFCRS
Electrocatalysis | Year: 2014

The preparation of multi-walled carbon nanotubes–NiO nanoparticles composites (MWCNT–NiO) is presented and the composites were used for modification of glassy carbon electrode for lactose electrooxidation in NaOH. Nickel oxide (NiO) was accumulated on multi-walled carbon nanotubes (MWCNT) by pulsed potential electrodeposition. The structure and nature of the MWCNT–NiO were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results show that NiO nanoparticles were homogeneously electrodeposited on the surfaces of MWCNTs. Also, the electrochemical behaviour of MWCNT–NiO nanoparticles composite in an aqueous solution of alkaline of lactose was studied using cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy (EIS). The peak on the voltammogram for MWCNT–NiO composite electrode in alkaline solutions of lactose was observed which was ascribed to the lactose oxidation in alkaline medium. The results obtained are discussed from the point of view of employment of the MWCNT–NiO composites for the catalytic electrodes of sugar-oxygen fuel cells. © 2013, Springer Science+Business Media New York. Source

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