Papers by Mohammad Yousefi
Electroanalysis, 2006
A pyrolytic carbon (PC) film electrode was fabricated by the chemical vapor deposition (CVD) meth... more A pyrolytic carbon (PC) film electrode was fabricated by the chemical vapor deposition (CVD) method. This report deals with the preparation, characterization and electrochemical behavior of this carbon film. Cyclic voltammetry, linear sweep voltammetry, Raman spectroscopy and scanning electron microscopy were employed to characterize the electrode. Low background current and capacitance were observed and the rate of charge transfer for Fe(CN) redox couple was determined via cyclic voltammetry. Also the effect of the anodic activation on the electrochemical activity was evaluated and characterized with respect to the sequence of voltage applied to the electrode. The excellent electrochemical activity and low background current are the reasons why this electrode is attractive for electroanalysis measurements with lower detection limit.
Analytica Chimica Acta, 2001
Analytical Chemistry, Jun 1, 2000
A PVC membrane sensor for cerium(III) ions based on 1,3,5-trithiane as membrane carrier was prepa... more A PVC membrane sensor for cerium(III) ions based on 1,3,5-trithiane as membrane carrier was prepared. The sensor has a linear dynamic range of 1.0 x 10(-1)-5.0 x 10(-5) M, with a Nernstian slope of 19.4+/-0.4 mV decade(-1), and a detection limit 3.0 x 10(-5) M. It has a fast response time of < 15 s and can be used for at least 5 months without any considerable divergence in potentials. The proposed sensor revealed comparatively good selectivities with respect to alkali, alkaline earth, and some transition and heavy metal ions and could be used in a pH range of 5.0-8.0. It was used as an indicator electrode in potentiometric titration of oxalate and fluoride ions and in determination of F- ion in some mouth wash preparations.
Separation Science and Technology, 2002
Rosaniline-grafted polyurethane foam (Ros-PUF) has been synthesized, by coupling polyether polyol... more Rosaniline-grafted polyurethane foam (Ros-PUF) has been synthesized, by coupling polyether polyol, rosaniline, and toluene diisocyanate, and characterized, by use of UV-visible and IR spectroscopy and thermogravimetric analysis. The Ros-PUF was used as a new sorbent for extraction of trace amounts of Cd(II) and Hg(II) from water by batch and column techniques. Cd(II) and Hg(II) were completely separated from 2-6 M HCl solution containing 1 M KSCN in 10-20 min. The kinetics and thermodynamics of sorption of the metal ions by Ros-PUF were studied. The average values of ∆H, ∆S, and ∆G for sorption of Cd(II) and Hg(II) by Ros-PUF were −54.38 kJ mol −1 , 159 J K −1 mol −1 , and-4.87 kJ mol −1 , respectively. The Dubinin-Radushkevich equation was used to explain the equilibrium isotherm. The sorption capacities of Ros-PUF were 0.12 and 0. 08 mmol g −1 for Cd(II) and Hg(II), respectively. The method has been successfully used to preconcentrate and remove Cd(II) and Hg(II) from tap water. Preconcentration factors were ~100 and recoveries were between 86.6 and 100% (average RSD ≈ 5.74).
Analytical Chemistry, Jun 1, 2000
A PVC membrane sensor for cerium(III) ions based on 1,3,5-trithiane as membrane carrier was prepa... more A PVC membrane sensor for cerium(III) ions based on 1,3,5-trithiane as membrane carrier was prepared. The sensor has a linear dynamic range of 1.0 x 10(-1)-5.0 x 10(-5) M, with a Nernstian slope of 19.4+/-0.4 mV decade(-1), and a detection limit 3.0 x 10(-5) M. It has a fast response time of < 15 s and can be used for at least 5 months without any considerable divergence in potentials. The proposed sensor revealed comparatively good selectivities with respect to alkali, alkaline earth, and some transition and heavy metal ions and could be used in a pH range of 5.0-8.0. It was used as an indicator electrode in potentiometric titration of oxalate and fluoride ions and in determination of F- ion in some mouth wash preparations.
Separation Science and Technology, 2002
An efficient method for preconcentration of trace amounts of Mn (II) and Ni (II) ions by using a ... more An efficient method for preconcentration of trace amounts of Mn (II) and Ni (II) ions by using a minicolumn (10 mm × 30 mm i.d.) �lled with a diimine derivative Schiff base on silica-gel has been reported. e retained analytes on the column were recovered with 5 mL of mixture of nitric acid 5 mol L −1 and methanol (1 : 1) and were determined by a �ame atomic absorption spectrometer. Different factors including pH of sample solution, sample volume, amount of sorbent, eluent volume, and interference of other ions have been studied and the optimized conditions developed were utilized for the trace determination of Mn (II) and Ni (II) in natural water samples. e recoveries for the analytes under the optimum working conditions were higher than 98%. e relative standard deviations of the determinations (10 replicate analyses) at 25 g L −1 of Mn (II) and Ni (II) were 2.5% and 2.3%, respectively. e limit of the detection (3s, 1 for analytes were found to be 0.20 g L −1 for Mn (II) and 0.15 g L −1 for Ni (II). e proposed method was applied to the analysis of natural water samples with satisfactory results.
Japanese Journal of Applied Physics, 2006
ABSTRACT Pb(Zr1-xTix)O3 (PZT) polycrystalline thin films were prepared by sol-gel and pulsed lase... more ABSTRACT Pb(Zr1-xTix)O3 (PZT) polycrystalline thin films were prepared by sol-gel and pulsed laser deposition techniques on Pt/Ti/SiO2/Si (Pt) and SrRuO3/LaAlO3 (SRO/LAO) substrates. Infrared reflectivity spectroscopy with oblique (45°) light incidence revealed both the 3LO (688 cm-1) phonon lineshape asymmetry decrease with increasing in thickness and the thinner, disordered boundary layer at the SRO/PZT interface independently of the film preparation method. The fatigue properties of PZT films were studied for various crystallographic orientations. It was observed that in the 52/48 PZT/SRO/LAO film, when the field is applied along the (001) direction, excellent fatigue resistance is obtained.
Japanese Journal of Applied Physics, 2006
ABSTRACT Pb(Zr1-xTix)O3 (PZT) polycrystalline thin films were prepared by sol-gel and pulsed lase... more ABSTRACT Pb(Zr1-xTix)O3 (PZT) polycrystalline thin films were prepared by sol-gel and pulsed laser deposition techniques on Pt/Ti/SiO2/Si (Pt) and SrRuO3/LaAlO3 (SRO/LAO) substrates. Infrared reflectivity spectroscopy with oblique (45°) light incidence revealed both the 3LO (688 cm-1) phonon lineshape asymmetry decrease with increasing in thickness and the thinner, disordered boundary layer at the SRO/PZT interface independently of the film preparation method. The fatigue properties of PZT films were studied for various crystallographic orientations. It was observed that in the 52/48 PZT/SRO/LAO film, when the field is applied along the (001) direction, excellent fatigue resistance is obtained.
Journal of the Brazilian Chemical Society, 2006
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Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2013
Dimethyl 1-(4-nitrobenzoyl)-8-oxo-2, 8-dihydro-1H-pyrazolo [5, 1-a] isoindole-2, 3-dicarboxylate ... more Dimethyl 1-(4-nitrobenzoyl)-8-oxo-2, 8-dihydro-1H-pyrazolo [5, 1-a] isoindole-2, 3-dicarboxylate has been used as an ionophore and o-nitrophenyloctyl ether as a plasticizer in order to develop a poly (vinyl chloride)-based membrane electrode for calcium ion detection. The sensors exhibit significantly enhanced response towards calcium (II) ions over the concentration range 8.0 x 10Г7 1.0 x 10Г1 M at pH 3.0-11 with a lower detection limit of 5.0 x 10Г7 M.
Background: Trace elements play important roles in carbohydrates and lipids metabolism. According... more Background: Trace elements play important roles in carbohydrates and lipids metabolism. According to some studies, trace elements concentrations are different in serum and urine of diabetic and healthy population. In this work, for the first time six trace elements (Zn, Cu, Mg, Mn, Cr, Se) concentration of scalp hair, nail, urine and serum of diabetes mellitus patients and control group were analyzed at the same time.
Abstract: Modification of proteins by nonenzymatic glycation is one of the underlying factors tha... more Abstract: Modification of proteins by nonenzymatic glycation is one of the underlying factors that contribute to the development of the complications of diabetes. Human serum albumin (HSA) is one of the major targets of interaction with glucose through the Maillard reaction. The effects of 1 and 5 mg/ml glucose concentrations, which are consistent with blood glucose levels found in diabetic patients, on human serum albumin were studied by circular dichroism and fluorescence spectroscopy in sodium phosphate buffer, pH 7.4.
As a result, the method was found to be linear over the concentration range of 16-440 pg/mL (r= 0... more As a result, the method was found to be linear over the concentration range of 16-440 pg/mL (r= 0.9962), with a limit of detection and quantitation of 4.5 and 16 pg/mL, respectively. Furthermore, the technique shows the requisite accuracy, sensitivity, precision, and selectivity to assay tetracycline in capsules. Key Words: Tetracycline, ultramicroelectrode, continuous cyclic voltammetry, flow injection analysis, fast Fourier transformation.
A Cu2+ ion-selective membrane microelectrode has been fabricated from poly vinyl chloride (PVC) m... more A Cu2+ ion-selective membrane microelectrode has been fabricated from poly vinyl chloride (PVC) matrix membrane containing a new symmetrical hexadentate Schiff, s base 2-{1-(E)-2-((Z)-2-{(E)-2-[(Z)-1-(2-hydroxyphenyl) ethylidene] hydrazono}-1-methylpropylidene) hydrazono] ethyl} phenol (HDNOS) as a neutral carrier, Potassium tetrakis (4-chlorophenyl) borate (KTpClPB) as an anionic excluder and o-nitrophenyloctyl ether (NPOE) as a plasticizing solvent mediator.
Cation-exchange separations of the light lanthanides (La3+, Ce3+, Pr3+ and Nd3+) on Nucleosil 100... more Cation-exchange separations of the light lanthanides (La3+, Ce3+, Pr3+ and Nd3+) on Nucleosil 100-5-SA ion-exchange column with use of α-hydroxyisobutyricacid (HIBA) as elution agent was investigated in this study. For easy detection and identification, fast Fourier transform continuous cyclic voltammetry (FFT-CCV) was used as detection method. The developed technique is very simple, precise, accurate, time saving, and economical, compared to previously reported methods.
Abstract The effects of DPG, IHP, GTP, GDP and GMP on the structure and stability of haemoglobin ... more Abstract The effects of DPG, IHP, GTP, GDP and GMP on the structure and stability of haemoglobin were electrochemically investigated with an iodide-modified silver electrode in 0.01 M KNO 3 at pH 7.0. Anodic and cathodic peaks of haemoglobin were observed at 250 mV and 12 mV with a formal potential value of 133 mV vs. Ag/AgCl. The effects of different concentrations of DPG, IHP, GTP, GDP and GMP on the anaerobic redox reaction were determined.
Abstract: Amongst organophosphate pesticides, the one most widely used and common environmental c... more Abstract: Amongst organophosphate pesticides, the one most widely used and common environmental contaminant is diazinon; thus methods for its trace analysis in environmental samples must be developed. Use of diazinon imprinted polymers such as sorbents in solid phase extraction, is a prominent and novel application area of molecular imprinted polymers. For diazinon extraction, high performance liquid chromatography analysis was demonstrated in this study.
For the fast morphine monitoring in flow injection systems a highly sensitive method is being int... more For the fast morphine monitoring in flow injection systems a highly sensitive method is being introduced in this work. The fast Fourier transformation with continuous cyclic voltammetry (FFTCV) in a flowing solution as a detection system was applied for the prompt morphine monitoring. Here it should be stressed that this technique is simple, precise, accurate, time saving and economical. This research includes the observation of the effects of various parameters on the sensitivity of the detection system.
英文摘要: A rapid method for the extraction and monitoring of nanogram level of Pb 2+ and Cu 2+ ions ... more 英文摘要: A rapid method for the extraction and monitoring of nanogram level of Pb 2+ and Cu 2+ ions using uniform silanized mesopor (SBA-15) functionalized with aminobenzenesulfonamide groups and flame atomic absorption spectrometry (FAAS) is presented. Aminobenzenesulfonamide functionalized SBA-15 was synthesized according to procedure in the literature and the presence of organic groups in the silica framework was demonstrated by FT-IR spectra.
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Papers by Mohammad Yousefi