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91.
92.
A sensitive adsorptive cathodic stripping voltammetry with H‐point standard addition method for simultaneous determination of uranium and cadmium has been developed. The trace amounts of these metal ions can be simultaneously determined using the Levodpa as complexing agent. Optimal conditions were: accumulation time 50 s, accumulation potential 0.0 mV, scan rate 40 mV s?1, supporting electrolyte 0.1 M ammonium buffer pH 9.6, and 1×10?5 M of Levodopa. The results revealed that the cadmium and uranium could be simultaneously determined by H‐point standard addition method with different concentration ratios of uranium to cadmium. The method was successfully applied in a several of real samples. 相似文献
93.
Babak Mokhtarani Ali Sharifi Hamid Reza Mortaheb Mojtaba Mirzaei Morteza Mafi Fatemeh Sadeghian 《The Journal of chemical thermodynamics》2009,41(12):1432-1438
Densities and viscosities of 1-butyl-3-methylimidazolium nitrate [Bmim][NO3], and its binaries with alcohol (ethanol, 1-propanol, or 1-butanol) were measured at different temperatures. The densities and viscosities of pure ionic liquid were correlated successfully by empirical equations. The Vogel–Fulcher–Tammann equations can fit the experimental data of viscosities for pure IL. Excess molar volume and viscosity deviations were calculated for the binaries. The excess molar volumes have negative deviations from the ideal solution. 相似文献
94.
HERAVI Majid M. BEHESHTIA Yahya S. KHORSHIDI Maliheh BAGHERNEJAD Bita BAMOHARRAM Fatemeh F. 《中国化学》2009,27(3):569-572
A simple, clean and environmentally benign route to the synthesis of 3-cyanopyridines is described via a one-pot multi-component reaction of 3,4-dimethoxyacetophenone, malonitrile or ethylcyanoacetate, aldehyde and ammonium acetate using heteropolyacids as heterogeneous and recyclable catalysts in very good yields. 相似文献
95.
Younes Ghasemi Sara Rasoul-Amini Mohammad Hossein Morowvat Mohammad Bagher Ghoshoon Mohammad Javad Raee Soraya Khoubani Narges Negintaji Fatemeh Nouri Rezvan Parvizi 《Chemistry of Natural Compounds》2009,45(6):824-828
A unicellular microalga, Chlorella vulgaris, was isolated from rice field and applied in the biotransformation experiment
of hydrocortisone (1). This strain has not been previously tested for hydrocortisone bioconversion. Fermentation was carried out in BG-11 medium
supplemented with 0.05% substrate at 25°C for 14 days incubation. The products obtained were chromatographically purified
followed by their characterization using spectroscopic methods. 11β,17α,20β,21-Tetrahydroxypregn-4-en-3-one (2), 11β,17β-dihydroxyandrost-4-en-3-one (3), and 11β-hydroxyandrost-4-ene-3,17-dione (4) were the main bioproducts in the hydrocortisone bioconversion. Bioreaction characteristics observed were 20-ketone reduction
for accumulation of compound 2 and side chain degradation of the substrate to prepare compounds 3 and 4. Time course study showed the accumulation of the product 2 from the second day of the fermentation and 3 as well as 4 from the third day. All the metabolites reached their maximum concentration in seven days. Microalgal 18S rRNA gene was also
amplified by PCR. PCR products were sequenced to confirm their authenticity as 18S rRNA gene of microalgae. The result of
PCR blasted with other sequenced microalgae in NCBI showed 100% homology to the 18S small subunit rRNA of six strains of Chlorella
vulgaris. 相似文献
96.
97.
98.
Susan Sadeghi Fatemeh Fathi 《Journal of inclusion phenomena and macrocyclic chemistry》2010,67(1-2):91-98
A new PVC membrane coated graphite electrode for cesium ion based on 4′,4″(5′)di–tert-butyl di-benzo-18-crown-6 (DTBDB18C6) as ionophore was prepared. The electrode shows a near Nernstian response of 57.0 ± 1.8 mV decade?1 over a wide activity range of 6.0 × 10?6–1.0 × 10?1 mol L?1 with a limit of detection 4.0 × 10?6 mol L?1. The proposed electrode is suitable for use in aqueous solution in the pH range of 3.0–9.5. It has a fast response time of 10 s and can be used for at least 1 month without any considerable divergence in potential. The selectivity coefficients for Cs+ ion with respect to ammonium, alkali, alkaline earth and some selected transition metal ions were determined and showed a superior selectivity over Li+, Na+ and alkaline earth metal ions. The new electrode was applied for determination of Cs+ in spiked tap water. The electrode was also used as indicator electrode in potentiometric titration of Cs+ with sodium tetraphenyl borate. 相似文献
99.
Nano-sized Cu6Sn5 alloy powders were prepared by a co-precipitation reductive route using a hydrothermal method at 80 °C. The nano-size and morphology of the synthesized Cu6Sn5 alloy powders were evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The obtained morphologies, chemical compositions are comparatively discussed. A variety of synthesis parameters, such as time, capping agent and sort of reductant, has an effect on the morphology of the obtained materials, and will be particularly highlighted. 相似文献
100.
Zahra Talebpour Mehregan Safari Fatemeh Molaabaci Ali Alizadeh Hassan Y. Aboul-Enein 《Chromatographia》2010,72(7-8):707-712
A novel poly(methyl methacrylate–ethyleneglycol dimethacrylate–acrylic acid) film has been introduced for coating on stir bars to sorptive extraction (SBSE). The effects of different contents of porogen, monomer, cross-linker, modifier and initiator during the solvent or bulk polymerization step on the mechanical property and solvent resistant of prepared sorptive stir bars were investigated. The evaluation of results were caused to obtain the four prepared sorptive stir bars with good mechanical stability and excellent resistance to organic solvents. The extraction efficiency of these prepared sorptive stir bars were investigated by liquid desorption-liquid chromatography-ultraviolet detection (LD-LC-UV) using N-Nitrosodiphenylamine as target analyte. SBSE assays showed the sorptive stir bar that prepared using solution polymerization method had the better recovery for N-Nitrosodiphenylamine in water samples. This sorptive stir bar showed good linearity and acceptable recoveries, as well as advantages such as sensitivity, simplicity, low cost and high feasibility. Based on atomic force microscopy (AFM) results, the average pore size of optimum prepared stir bar using solvent polymerization method was obtained ~9 nm. The thermal gravity (TG) and differential scanning calorimetric (DSC) results showed this polyacrylate film has high thermal stability. 相似文献