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31.
Mohammad Ali Karimi Rasul Shahin Sayed Zia Mohammadi Abdolhamid Hatefi‐Mehrjardi Javad Hashemi Javad Yarahmadi 《中国化学会会志》2013,60(11):1339-1346
A new solid phase extraction (SPE) method has been developed for the speciation of Cr(III) and Cr(VI). This method is based on the adsorption of Cr(VI) on modified alumina‐coated magnetite nanoparticles (ACMNPs). Total chromium in different samples was determined as Cr(VI) after oxidation of Cr(III) to Cr(VI) using H2O2. The chromium concentration has been determined by flame atomic absorption spectrometric (FAAS) technique and amount of Cr(III) was calculated by substracting the concentration of Cr(VI) from total chromium concentration. The effect of parameters such as pH, amount of adsorbent, contact time, sample volume, eluent type, H2O2 concentration and cetyltrimethylammonium bromide (CTAB) concentration as modifier on the quantitative recovery of Cr(VI) were investigated. Under the optimal experimental conditions, the preconcentration factor, detection limit, linear range and relative standard deviation (RSD) of Cr(VI) were 140 (for 350 mL of sample solution), 0.083 ng mL?1, 0.1‐10.0 ng mL?1 and 4.6% (for 5.0 ng mL?1, n = 7), respectively. This method avoided the time‐consuming column‐passing process of loading large volume samples in traditional SPE through the rapid isolation of CTAB@ACMNPs with an adscititious magnet. The proposed method was successfully applied to the determination and speciation of chromium in different water and wastewater samples and suitable recoveries were obtained. 相似文献
32.
A simple and convenient method for the aromatization of Hantzsch 1,4-dihydropyridines to the corresponding pyridines is achieved via combination of aluminum or ferric nitrates and silica sulfuric acid as environmentally friendly and novel oxidizing media. This oxidation was carried out in dichloromethane under heterogeneous conditions with good to excellent yields. 相似文献
33.
An efficient approach for the preparation of functionalized 2‐aryl‐2,5‐dihydro‐5‐oxo‐4‐[2‐(phenylmethylidene)hydrazino]‐1H‐pyrroles is described. The four‐component reaction between aldehydes, NH2NH2?H2O, dialkyl acetylenedicarboxylates, and 1‐aryl‐N,N′‐bis(arylmethylidene)methanediamines proceeds in EtOH under reflux in good‐to‐excellent yields (Scheme 1). The structures of 4 were corroborated spectroscopically (IR, 1H‐ and 13C‐NMR, and EI‐MS, and, in the case of 4f , by X‐ray crystallography). A plausible mechanism for this type of reaction is proposed (Scheme 2). 相似文献
34.
Mohammad Mazloum-Ardakani Javad Safari Parvin Pourhakkak Mohammad Ali Sheikh-Mohseni 《International journal of environmental analytical chemistry》2013,93(14):1638-1649
A PVC (poly vinyl chloride) membrane electrode for lead ion based on 2-(((E)-2-((E)-1-(2-hydroxyphenyl)methyliden)hydrazono)metyl)phenol (HMHMP) as a membrane carrier was prepared. This electrode exhibited linear response with Nernstian slope of 29.2?±?0.2?mV per decade within the concentration range of 2.0?×?10?7–1.0?×?10?1?M lead ion. The limit of detection, as determined from the intersection of the extrapolated linear segments of the calibration plot, was 8.0?×?10?8 M. The electrode exhibited high selectivity for Pb (II). The response time of the electrode was about 5–10?s for different concentrations. The electrode is suitable for use in aqueous solutions in a pH range of 5.0–7.5. It was used as an indicator electrode in a titration of Pb (II) with chromate at constant pH. This electrode was used for the determination of lead in ore samples, and the results were in agreement with those obtained with an atomic absorption spectroscopy (AAS) method. Also lead selective electrode was used for monitoring of lead in spiked samples of the Zayanderud River and waste water by the potentiometry technique. 相似文献
35.
Hamideh Sharifi Noghabi Gholam Hossein Rounaghi Mohammad Hossein ArbabZavar Javad Ebrahimi 《Russian Journal of General Chemistry》2014,84(7):1429-1433
We report on conductometric study of complexation between benzylbisthiosemicarbazone [(2E,2′E)-2,2′-(1,2-diphenylethane-1,2-diylidene)bis(hydrazine-1-carbothioamide)] with Zn2+, Cr3+, Co2+, and Ni2+ cations at different temperatures in acetonitrile-dimethylformamide binary solvents of varied composition. The equilibrium constant and standard thermodynamic parameters (Δc H 0 and Δc S 0) of the complexes formation have been determined and found to be dependent on the binary solvent composition, the metal ion nature, and temperature. 相似文献
36.
Soodabeh Davaran Mohammad Sadeghinia Zahra Jamalpoor Vahideh Raeisdasteh Hokmabad Mehdi Doosti-Telgerd Ansar Karimian Zahra Sadeghinia Javad Khalilifard Akram keramt Farzad Moradikhah Ali Sadeghinia 《Electrophoresis》2020,41(12):1081-1094
Microfluidic system, or lab-on-a-chip, has grown explosively. This system has been used in research for the first time and then entered in the clinical section. Due to economic reasons, this technique has been used for screening of laboratory and clinical indices. The microfluidic system solves some difficulties accompanied by clinical and biological applications. In this review, the interpretation and analysis of some recent developments in microfluidic systems in biomedical applications with more emphasis on tissue engineering and cancer will be discussed. Moreover, we try to discuss the features and functions of microfluidic systems. 相似文献
37.
Javad Kalbasi Roozbeh Rahmati Fatemeh Mazaheri Omid 《Research on Chemical Intermediates》2020,46(7):3413-3430
Research on Chemical Intermediates - Acid–base copolymer materials are of considerable interest because of their fundamental implications for acid–base bifunctional catalysis... 相似文献
38.
Mohamad Javad Tahmasebi Birgani Fatemeh Seif Nahid Chegeni Mohamad Reza Bayatiani 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(3):1367-1370
In consideration the radiological properties of materials and studying the scattering processes in atomic and nuclear physics,
the effective atomic and mass numbers is widely employed. These numbers have been calculated for any mixed or composite materials
in interaction with high energy photons (Linac in radiation therapy). A pair equation in terms of these numbers is obtained.
The first equation has been derived from the conservation of mass energy law and the second by minimizing the binding energy
from the semiempirical mass formula (Myers and Swiatecki formula) that gives a relation between atomic and mass numbers for
stable nuclei approximately. By these equations one can obtain the effective atomic and mass numbers for any compound or mixed
materials uniquely. These numbers are calculated for some materials and compared with the other studies. 相似文献
39.
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