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排序方式: 共有199条查询结果,搜索用时 62 毫秒
11.
Afsaneh Safavi Norouz Maleki Fatemeh Honarasa Fariba Tajabadi Fatemeh Sedaghatpour 《Electroanalysis》2007,19(5):582-586
A new type of potentiometric sensor based on a recently constructed carbon ionic liquid electrode (CILE) is described. Two kinds of ionic liquids, i.e., N‐octylpyridinium hexafluorophosphate (OPFP) and 1‐butyl‐3‐methylimidazoluim hexafluorophosphate (BMFP) were tested as binder for construction of the carbon composite electrode. The characteristics of these electrodes as potentiometric sensors were evaluated and compared with those of the traditional carbon paste electrode (CPE). The results indicate that potentiometric sensors constructed with ionic liquid show an increase in performance in terms of Nernstian slope, selectivity, response time, and response stability compared to CPE. 相似文献
12.
Hoda Keipour Mohammad A.Khalilzadeh Abolfazl Hosseini Afsaneh Pilevar Daryoush Zareyee 《中国化学快报》2012,23(5):537-540
Potassium fluoride doped natural zeolite was found to be an efficient and selective solid base catalyst for 1,4-Michael addition. The catalyst is easily prepared and the workup procedure simplified by simple filtration.All products were obtained in high yields as well as short reaction times. 相似文献
13.
Ebrahim Soleimani Mohammad Mehdi Khodaei Afsaneh Taheri Kal Koshvandi 《Comptes Rendus Chimie》2012,15(4):273-277
An environmentally friendly and simple method for the synthesis of alkyl nitriles or β-cyanocarbonyls via a one-pot three-component reaction of Meldrum's acid, aldehydes and sodium cyanide in water, without using any catalyst or activation at room temperature is reported. 相似文献
14.
Benzo[b][1,4]oxazines have been synthesized in good to excellent yields in the presence of the ionic liquid 1-butyl-3-methylimidazolium bromide [bmim]Br under relatively mild conditions without any added catalyst, The method offers the advantages of good yields and short reaction times, and the ionic liquid can be easily separated from the product and reused. 相似文献
15.
Hydroxyapatite Wrapped Multiwalled Carbon Nanotubes/Ionic Liquid Composite Electrode: A High Performance Sensor for Trace Determination of Lead Ions 下载免费PDF全文
A nanocomposite consisting of multiwalled carbon nanotubes wrapped with hydroxyapatite (HA/MWCNTs) was used in the construction of a new composite paste electrode using an ionic liquid as the binder. The stable surface in aqueous solutions as well as the high sorptive behaviors towards heavy metal ions and the favorable charge transfer make the electrode highly efficient especially for stripping or adsorptive analysis. The analysis of Pb2+ as a model of heavy metal ions has been performed. Good sensitivity, detection limit, selectivity and reproducibility were obtained for the suggested sensor. The linear range of the electrode response covered four orders of magnitude (1 nM–10 µM), in two linear ranges. The obtained detection limit for Pb2+ was 2×10?11 M. 相似文献
16.
N-(Thiazol-2-yl) benzamide 1 substructures are found in some of bioactive compounds. In some of protein/ligand co-crystals, the 1 moiety adopts a conformer in which the amide O and the thiazole S atoms are close. In fact, in the crystalline structure of 1 , the O—S distance is even shorter than Van der Waals radius. Although the natural bond orbital analysis finds a weak stabilizing interaction between O and S atoms, the attractive dipole–dipole interaction between the amide N─H and thiazole N atom seems to play a more significant role. Moreover, an intramolecular O—H hydrogen bonding in dimeric forms found to have an important role in the conformation preference of 1 . Computational details for the stability of conformers have been discussed using quantum theory of atoms in molecules, natural bond orbital (NBO) and noncovalent interaction index analysis. 相似文献
17.
Ali A. Moshfegh Effat Beladi Lida Radnia Afsaneh S. Hosseini Soosan Tofigh Gholam H. Hakimelahi 《Helvetica chimica acta》1982,65(4):1264-1270
The synthesis of the title compounds ( 1 and 3 ) is described. Some of the compounds prepared were found to be active against a number of pathogenic microorganisms in vitro. Structure-activity relationship is briefly discussed. 相似文献
18.
A sensitive and selective kinetic method is proposed for the determination of nanogram amounts of copper. The method is based on the catalytic effect of copper on the reduction of Ponceau S by sodium sulfide in an alkaline media. The rate of the reaction is monitored spectrophotometrically at 560 nm. The method allows determination of copper concentrations in the range 2-400 ng ml(-1) with a relative standard deviation of approximately 2%. The proposed method, which is highly selective to copper, has been applied satisfactory to its determination in real samples. 相似文献
19.
Simultaneous determination of Fe(II) and Fe(III) or selective determination of each oxidation state of iron in the presence of the other one by H-point standard addition method (HPSAM) is described. Mixed reagents of 1,10-phenanthroline and salicylic acid was used as a selective chromogenic system for speciation of Fe(II) and Fe(III). It was shown that with appropriate selection of wavelength pairs, both Fe(II) and Fe(III) can be considered as analyte. The results showed that Fe(II) and Fe(III) can be determined simultaneously with the concentration ratios of Fe(II) to Fe(III) varying from 10:1 to 1:20 in the mixed sample. The accuracy and precision of the method are all satisfactory. 相似文献
20.
A method for sensitive and selective determination of silver based on the catalytic effect of silver(I) ion on the oxidation of Janus Green by peroxodisulfate is described. o-Phenanthroline is used as an activator. The rate of the decrease in absorbance of Janus Green (at 615 nm) is proportional to the concentration of silver in the range of 0.3-4.0 ng mL(-1) and 4.0-500.0 ng mL(-1). The theoretical limit of detection was 0.25 ng mL(-1). The method is free from most interferences. The method was applied to the determination of silver in plants (the uptake of silver by plants), in photographic solutions, lake water and several synthetic samples. 相似文献