Mahmood Chamsaz

Ferdowsi University Of Mashhad, Mashad, Razavi Khorasan, Iran

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Publications (31)68.66 Total impact

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    ABSTRACT: This paper proposes the possibility of applying first order calibration methods for unknown sample(s) with unmodeled component(s) using the differential spectra obtained from subtracting of the absorbance spectra of sample that are recorded in two different environments. The main interest is that the method can be performed to quantify systems if the spectra of their unmodeled component(s) are the same in two different phases using first order calibration methods. The procedure demonstrates simultaneous determination of new fuchsine, crystal violet and malachite green in the presence of sunset yellow, tartarazine and amaranth as unmodeled interferences, whose spectra differ in aqueous and nonionic micellar solution of Triton X-100. The obtained satisfactory results indicate the successful applicability of the proposed method in complex samples.
    Journal of Analytical Chemistry 01/2015; 70(1). DOI:10.1134/S1061934815010190 · 0.81 Impact Factor
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    ABSTRACT: The complextion reaction between Y3+ cation with macrocyclic ligand, 4′-nitrobenzo-18-crown-6 (4′NB18C6), was studied in acetonitrile-methanol (AN-MeOH), acetonitrile-1,2-dichloroethane (AN-DCE), acetonitrile-dimethylformamide (AN-DMF) and acetonitrile- ethylacetate (AN-EtOAc) binary mixed solvent solutions at different temperatures using the conductometric method. The conductance data show that in most cases, the stoichiometry of complex formed between 4′NB18C6 and Y3+ cation is 1:1 [M:L], but in the case of AN-DCE binary solution (mol%DCE=50) at 15, 25 and 35°C, a 2:1 [M2:L] and also a 2:2 [M2:L2] complexes are formed in solution.The results show that the stoichiometry of the complex formed between 4′NB18C6 and Y3+ cation changes with the composition of the mixed solvents and even with temperature. The stability constant of the 1:1 complex was determined using a computer program, GENPLOT. The stability order of (4′NB18C6.Y)3+ complex in pure studied solvents at 25°C was found to be: EtOAc > AN > MeOH > DMF and in the case of the mixed solvent solutions with 25 mole percent of AN at 25°C was: AN-DCE > AN-EtOAc > AN-MeOH ∼ AN-DMF. The values of stability constant (logKf) of (4′NB18C6.Y)3+ complex which was obtained from conductometric data, show that the stability of the complex is not only affected by the nature and composition of the solvent system, but it is also influenced by the temperature. In all cases, a non-linear behavior is observed for changes of logKf of the (4′NB18C6.Y)3+ complex versus the composition of the binary mixed solvents. The values of standard thermodynamic quantities (ΔH°c and ΔS°c) for the complexation process which were obtaind from temperature dependence of the stability constant of (4′NB18C6.Y)3+ complex, show that depending on the solvent system, in most cases, the complex is enthalpy and also entropy stabilized, but in some cases, it is estabilized or destabilized from these view points.
    Arabian Journal of Chemistry 08/2014; DOI:10.1016/j.arabjc.2014.07.003 · 2.68 Impact Factor
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    ABSTRACT: A new flow injection method coupled to an electrochemical hydride generator with atomic absorption spectrometry was proposed for determination of cadmium. The influence of the experimental parameters such as cathode material, catholyte type, sample volume, catholyte flow rate, temperature of the atomizer, catholyte concentration, carrier gas flow rate, electrolytic current and cathode surface area on the analytical response was studied. Under the optimized conditions, the calibration curve was linear in the range of 2–50 ng mL− 1 of Cd. A concentration detection limit (3σb, n = 9) of 0.61 ng mL− 1 Cd and a relative standard deviation of 5.1% (RSD, n = 9) for 20 ng mL− 1 Cd were obtained. The potential interferences from various ions were also evaluated. The accuracy of the method was verified by the determination of cadmium in a certified reference material. The calculated concentration of Cd in CRM was found to be in good agreement with the certified value.
    Microchemical Journal 05/2013; 108:188–192. DOI:10.1016/j.microc.2012.10.017 · 3.58 Impact Factor
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    ABSTRACT: Headspace single-drop microextraction (HS-SDME) coupled with gas chromatography with electron capture detection (GC-ECD) was used for quantification of total iodine in milk based samples of infant formula. In this procedure 3 μL of a mixture containing 1-octanol and 3-pentanone was exposed to the headspace of a 5 mL acidic (H2SO4, 2 mol L−1) aqueous solution containing 1.5 mol L−1 ZnSO4 for 30 minutes followed by addition of 1 mL of 1 mol L−1 H2O2 for in situ generation of iodine. Optimization of the microextraction system was carried out using the Taguchi experimental design method. The limit of detection was determined to be 250 ng L−1 with an enrichment factor of 150. The repeatability, expressed as a relative standard deviation, was 1.9% (n = 6). The linear calibration working range was between 0.75 and 2000 μg L−1 (r2 = 0.998). The method was successfully applied for determination of iodine in milk based samples of infant formula.
    Analytical methods 01/2013; 5(3):778-783. DOI:10.1039/C2AY25931A · 1.94 Impact Factor
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    ABSTRACT: A novel electrochemical hydride generation (ECHG) system working in flow-injection (FI) mode was developed for determination of cadmium coupled to an electrically heated quartz tube atomizer (QTA) by atomic absorption spectrometry (AAS). A Plackett-Burman experimental design for screening has been used to evaluate the influence of several variables on the analytical response. Then, the significant parameters such as the concentration of NaCl in catholyte, applied electrolytic current and flow rate of carrier gas have been simultaneously optimized using a central composite design (CCD). Under the optimized conditions, the detection limit (3σ(b), n=9) was found to be 0.51 ng mL(-1) Cd and the relative standard deviation (RSD) for nine replicate analyses of 20 ng mL(-1) Cd was 6.5%. The calibration curve was linear in the range of 2-50 ng mL(-1) of Cd. The potential interferences from various ions were also evaluated. The analysis of a reference material showed good agreement with the certified value. The proposed method was successfully applied to the determination of Cd in tap water sample.
    Talanta 08/2012; 97:229-34. DOI:10.1016/j.talanta.2012.04.022 · 3.51 Impact Factor
  • Arabian Journal of Chemistry 05/2012; DOI:10.1016/j.arabjc.2012.05.003 · 2.68 Impact Factor
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    ABSTRACT: The objective of this study was to compare the performance of an artificial neural network (ANN) model and a 3-phase segmented linear regression model to describe the relationship between flock age and hatchability in broiler breeder flocks. The predictive quality of these models was tested for an external validation set of 14 wk, randomly chosen from 39 wk. The accuracy of the models was determined by the r2 value, mean square error, bias, and Theil’s U-statistic parameters. The r2 values of the 3-phase segmented linear regression and ANN models were 0.4003 and 0.9984, respectively. Therefore, the ANN produced more accurate predictions of hatchability than the 3-phase segmented linear regression model. We conclude, based on the results of this study in commercial broiler breeder flocks, that hatchability is a function of flock age and that the relationship can be described by an ANN model.
    The Journal of Applied Poultry Research 08/2011; 20(3):447-453. DOI:10.3382/japr.2010-00249 · 0.59 Impact Factor
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    ABSTRACT: Competitive permeation of seven metal cations from an aqueous source phase containing equimolar concentrations of Co2+, Fe3+, Cd2+, Cu2+, Zn2+, Ag+ and Pb2+ metal ions at pH 5 into an aqueous receiving phase at pH 3 through an organic phase facilitated by 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane (Kryptofix5) as a carrier was studied as bulk liquid membrane transport. The obtained results show that the carrier is highly selective for Ag+ cation and under the employed experimental conditions, it transports only this metal cation among the seven studied metal cations. The effects of various organic solvents on cation transport rates have been demonstrated. Among the organic solvents involving nitrobenzene (NB), chloroform (CHCl3), dichloromethane (DCM) and 1,2-dichloroethane (1,2-DCE) which were used as liquid membrane, the most transport rate was obtained for silver (I) cation in DCM. The sequence of transport rate for this cation in organic solvents was: DCM > CHCl3 > 1,2-DCE > NB. The competitive transport of these seven metal cations was also studied in CHCl3–NB and CHCl3–DCM binary solvents as membrane phase. The results show that the transport rate of Ag+ cation is sensitive to the solvent composition and a non-linear relationship was observed between the transport rate of Ag+ and the composition of these binary mixed non-aqueous solvents. The influence of the stearic acid, palmitic acid and oleic acid as surfactant in the membrane phase on the transport of the metal cations was also investigated.
    Arabian Journal of Chemistry 06/2011; 27. DOI:10.1016/j.arabjc.2011.06.013 · 2.68 Impact Factor
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    ABSTRACT: A novel and extremely sensitive method for extn. and detn. of cadmium in aq. samples by liq. phase micro extn. combined with electrothermal at. absorption spectrometry using a new ligand is described. In this method Cd2+ in pH 4 during 20 min extn. time at 20° is reacted with S-methyl-3-salicylidene dithiocarbazate dissolved in 4 μL of chloroform micro drop. After extn., the micro drop was retracted and directly transferred into a graphite tube coated by palladium as chem. modifier. The type of org. solvent, vol. of org. solvent, pH, temp. and extn. time were optimized. Using 10 mL sample soln. an enrichment factor of 100 was obtained. The detection limit is 6 pg mL-1 based on 3Sb and relative std. deviation for five replicate anal. of 0.2 ng mL-1 Cd2+ was 4.9%. The calibration curve was linear in the range of 6 pg mL-1 to 1.0 ng mL-1 with a sensitivity of 1.0 pg mL-1. This method was used for detn. of cadmium in tap water, waste water, sea water, soil and reliability of the method was evaluated using two ref. materials. [on SciFinder(R)]
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    ABSTRACT: A novel and extremely sensitive method for extn. and detn. of cadmium in aq. samples by liq. phase micro extn. combined with electrothermal at. absorption spectrometry using a new ligand is described. In this method Cd2+ in pH 4 during 20 min extn. time at 20° is reacted with S-methyl-3-salicylidene dithiocarbazate dissolved in 4 μL of chloroform micro drop. After extn., the micro drop was retracted and directly transferred into a graphite tube coated by palladium as chem. modifier. The type of org. solvent, vol. of org. solvent, pH, temp. and extn. time were optimized. Using 10 mL sample soln. an enrichment factor of 100 was obtained. The detection limit is 6 pg mL-1 based on 3Sb and relative std. deviation for five replicate anal. of 0.2 ng mL-1 Cd2+ was 4.9%. The calibration curve was linear in the range of 6 pg mL-1 to 1.0 ng mL-1 with a sensitivity of 1.0 pg mL-1. This method was used for detn. of cadmium in tap water, waste water, sea water, soil and reliability of the method was evaluated using two ref. materials. [on SciFinder(R)]
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    ABSTRACT: A novel and extremely sensitive method for extn. and detn. of bismuth in aq. samples by liq. phase micro extn. (LPME) combined with electrothermal at. absorption spectrometry using a new ligand is described. In this method Bi3+ in pH 6 during 20 min extn. time at 20° is reacted with S-methyl-3-salicylidene dithiocarbazate dissolved in 4 μL of chloroform microdrop. After extn., the microdrop was retracted and directly transferred into a graphite tube coated by palladium and tungsten with co-injection of tartaric acid as chem. modifier. The type of org. solvent, vol. of org. solvent, pH, temp., and extn. time were optimized. Using 10 mL sample soln. an enrichment factor of 100 was obtained. The detection limit was calcd. to be 19 pg mL-1 based on 3Sb and RSD for 5 replicate anal. of 0.5 ng mL-1 Bi3+ was 4.8 %. The calibration curve was linear in the range of 19 pg mL-1 to 2.4 ng mL-1 with a sensitivity of 4.0 pg mL-1. This method was used for detn. of bismuth in tap water, wastewater, seawater, soil and reliability of the method was evaluated using two ref. materials. [on SciFinder(R)]
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    ABSTRACT: A traditional belief in Iranian culture indicates that parental consumption of chicory leaves (Chicorium intybus L.) affects the gender of newborns. The aim of this study was to investigate the effect of aqueous extract of chicory on offspring sex ratio in rat. All rats in experimental groups 1 and 2 were i.p. injected with either 1.0 or 0.7 g/kg body weight (LD50 = 2.244 g/kg) of an aqueous extract of chicory leaves for 30 days at 72 h intervals. The control rats were injected with distilled water in the same manner. After the 8th injection, blood pH, and Na(+), K(+), Ca(2+) and Mg(2+) serum levels, were measured in all groups. On day 30, all the rats were mated within and between groups. The results revealed that in comparison with the control group, there were significant increases (p < 0.01) in Na(+) and K(+) levels, as well as the sex ratio of male to female offspring (10.23%) in experimental group 1. Therefore, it can be concluded that the administration of chicory leaf extract has a significant effect on the sex ratio of the rat offspring.
    Phytotherapy Research 09/2010; 24(9):1417-21. DOI:10.1002/ptr.3172 · 2.40 Impact Factor
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    Mahdi Karimi, Mohammad H Entezari, Mahmood Chamsaz
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    ABSTRACT: Kinetic and thermodynamic studies were carried out for the adsorption of nitrate ion from aqueous solutions onto modified beet residue and for desorption from the sorbent to the solution in batch experiments. The beet residue was modified by epichlorohydrin in the presence of pyridine. The experiments were conducted in the presence and absence of ultrasound. The removal of this ion was examined by varying experimental conditions such as the amount of sorbent, contact time, concentration, and temperature. It was found that more than 90% of nitrate ion was removed in less than 2 min from the solution. Results indicate that the adsorption of nitrate in the presence of ultrasound was higher at lower temperature (10 degrees C) and it was lower at higher temperatures with respect to the control method (without ultrasound). In the case of desorption study, the amount of desorption was higher in the presence of ultrasound than its absence at different applied temperatures. The Langmuir isotherm model fits adequately the experimental data for adsorption and desorption studies. In point of kinetics, the second-order kinetic model describes the sorption process for this ion. The thermodynamic parameters such as DeltaG degrees , DeltaH degrees , and DeltaS degrees were determined for the sorption of NO(3)(-) from the temperature dependence of the sorption process.
    Ultrasonics Sonochemistry 04/2010; 17(4):711-7. DOI:10.1016/j.ultsonch.2009.12.002 · 3.82 Impact Factor
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    ABSTRACT: An electrochemical hydride generation (ECHG) technique was developed to improve the determination of thallium by atomic spectrometry. The technique is based on the catholyte variation system for production of thallium hydride. Using Pb-Sn alloy as cathode, a transient peak shaped signal was achieved and its height, the maximum absorbance value, was taken as an analytical parameter. Parameters that might affect the hydride generation efficiency were investigated and the analytical performance of the method under the optimized experimental conditions was assessed. The linear range was 1-250 ng mL(-1) for thallium and the relative standard deviation of the method was 4.2% (RSD, n=7). The LOD for thallium was found to be 0.8 ng mL(-1), showing a significant improvement relative to conventional chemical hydride generation techniques. The proposed method was applied to the determination of thallium in unalloyed zinc standard reference material. This method offers high sensitivity, simplicity, rapidness, freeness from reagent and low acid consumption.
    Talanta 08/2009; 79(2):302-7. DOI:10.1016/j.talanta.2009.03.052 · 3.51 Impact Factor
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    ABSTRACT: The complexation reaction between UO2 2+ cation with macrocyclic ligand, 18-crown-6 (18C6), was studied in acetonitrile–methanol (AN–MeOH), nitromethane–methanol (NM–MeOH) and propylencarbonate–ethanol (PC–EtOH) binary mixed systems at 25°C. In addition, the complexation process between UO2 2+ cation with diaza-18-crown-6 (DA18C6) was studied in acetonitrile–methanol (AN–MeOH), acetonitrile–ethanol (AN–EtOH), acetonitrile–ethylacetate (AN–EtOAc), methanol–water (MeOH–H2O), ethanol–water (EtOH–H2O), acetonitrile–water (AN–H2O), dimethylformamide–methanol (DMF–MeOH), dimethylformamide–ethanol (DMF–EtOH), and dimethylformamide–ethylacetate (DMF–EtOAc) binary solutions at 25°C using the conductometric method. The conductance data show that the stoichiometry of the complexes formed between (18C6) and (DA18C6) with UO2 2+ cation in most cases is 1:1 [M:L], but in some solvent 1:2 [M:L2] complex is formed in solutions. The values of stability constants (logKf) of (18C6·UO2 2+) and (DA18C6·UO2 2+) complexes which were obtained from conductometric data, show that the nature and also the composition of the solvent systems are important factors that are effective on the stability and even the stoichiometry of the complexes formed in solutions. In all cases, a non-linear relationship is observed for the changes of stability constants (logKf) of the (18C6·UO2 2+) and (DA18C6·UO2 2+) complexes versus the composition of the binary mixed solvents. The stability order of (18C6·UO2 2+) complex in pure studied solvents was found to be: EtOH>AN≈NM>PC≈MeOH, but in the case of (DA18C6·UO2 2+) complex it was : H2O>MeOH>EtOH.
    Journal of Inclusion Phenomena 06/2009; 64(1):49-56. DOI:10.1007/s10847-009-9535-8 · 1.43 Impact Factor
  • Spectrochimica Acta Part B Atomic Spectroscopy 02/2009; DOI:10.1016/j.sab.2009.01.014 · 3.15 Impact Factor
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    ABSTRACT: The complexation reactions between some rare earth metal cations (Ln; Y3+, La3+ and Ce3+) with 18-crown-6 (18C6), dicyclohexyl-18-crown-6 (DC18C6), benzo-18-crown-6 (B18C6) and decyl-18-crown-6 (Dec18C6), have been studied in methanol–acetonitrile (MeOH–AN) and methanol–water (MeOH–H2O) binary mixtures using a competitive spectrophotometric method. 2-(2-thiazolylazo)-4-methyl phenol (TAC or L) was used as colorimetric complexant. It was found that the selectivity order of TAC for Ln cations is highly changed with changing the composition of the mixed solvents. Moreover, as the concentration of acetonitrile increases in MeOH–AN binary mixture, the stability of Ln–TAC complexes increases and passes through a maximum at a certain mole fraction of acetonitrile. In addition, the stability of Ln–crown ether complexes increases with increasing the concentration of methanol in MeOH–H2O and acetonitrile in MeOH–AN binary solutions. A non linear behaviour was observed for variation of stability constants of all complexes versus the composition of the mixed solvents. The results show that 18C6 generally forms more stable complexes with La3+ and Ce3+ cations than DC18C6 in methanol and MeOH–H2O binary mixtures, while this sequence is reversed in the methanol-acetonitrile binary mixtures which are rich with respect to acetonitrile.
    Journal of Inclusion Phenomena 01/2009; 63(1):43-52. DOI:10.1007/s10847-008-9487-4 · 1.43 Impact Factor
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    ABSTRACT: In recent years there has been considerable interest in the synthesis and separation of enantiomers of organic compounds especially because of their importance in the biochemistry and pharmaceutical industry. High-performance liquid Chromatography is a very useful method for the direct separation of enantiomers. However, about 30−40 years ago, commercially available chiral stationary phases were very limited. Researchers developed many novel chiral stationary phases for gas and liquid chromatography, and found these phases were effective practically to the separation and analysis of various chiral compounds. Enantioseparation of drugs with multiple chiral centers is challenging. This review describes resolution of some drugs with multiple chiral centers using polysaccharide-type chiral stationary phases.
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    ABSTRACT: Aluminium was determined in a weakly alkaline medium by reaction with alizarin at trace level. Flotation of the complex was carried out with heptane, followed by dissolution in N, N-dimethylformamide (DMF) for subsequent spectrophotometric determination. The molar absorptivity was 2.92×10 mol cm at 518 run. Beer's law was obeyed in the range 5–80 μg/1 and the detection limit was 0.4μg/l.The reliability of the procedure was confirmed by determination of a sample of milk with Graphite Furnace Atomic Absorption Spectrophotometric method (GFAAS). The precision and accuracy of the method were both acceptable via F and tests at the 95% confidence level.
    Analytical Letters 02/2008; 33(8):1625-1633. DOI:10.1080/00032710008543149 · 0.98 Impact Factor
  • M Chamsaz, A Safavi, J Fadaee
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    ABSTRACT: The kinetic methodology based on the difference of reaction rates, is based on the reaction between a common oxidizing agents such as tris(1,10-phenanthroline) and iron(III) complex (ferriin, [Fe (phen)3]3+) in the presence of citrate and spectrophotometrically, monitoring the changes of absorbance at the maximum wavelength of 511 nm. Experimental conditions such as pH, reagents and citrate concentrations were optimized, and the data obtained from the experiments were processed by several chemometric approaches, such as artificial neural network (ANN) and partial least squares (PLS). A set of synthetic mixtures of carbidopa (CD), levodopa (LD) and methyldopa (MD) was evaluated and the results obtained by the applications of these chemometric approaches were discussed and compared. It was found that the back propagation artificial neural network (BP-ANN) method afforded better precision relatively than those of radial basis function artificial neural networks (RBF-ANN) and PLS. The proposed method was also applied satisfactorily to the determination of carbidopa, levodopa and methyldopa in real samples.
    Analytica chimica acta 12/2007; 603(2):140-6. DOI:10.1016/j.aca.2007.09.006 · 4.52 Impact Factor