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991.
Monitoring of estradiol and its metabolites in biological samples is essential for the accurate diagnosis of a number of endocrine diseases. In this study, a sensitive, precise and specific GC–MS/MS method for the quantification of 17β-estradiol (17-BE) and its main metabolite, 2-methoxyestradiol (2-MEOE), in plasma was developed and validated. Plasma concentrations of these steroids are currently investigated as diagnostic markers for pre-eclampsia, a systematic disorder of pregnancy and a leading cause of maternal and fetal morbidity and mortality worldwide. 相似文献
992.
《Analytical letters》2012,45(10):723-728
Abstract A new method for the end-point detection in complexometric titration using a tensammetric wave of organic reagents such as oxine and alizarin complexone (ALC) was studied. The tensammetric wave of these reagents disappears by their chelate formation and reappears by the liberation of free indicator during the exchange reaction between indicator chelate and EDTA. This mechanism is utilized for the end-point detection in complexometric titration of metals. Since the sensitivity of tensammetric wave is extremely high, very sharp end-point can be obtained for the titration of metals even in the concentration of 10?5M. 相似文献
993.
Jian-Wen ShiHao-Jie Cui Jian-Wei ChenMing-Lai Fu Bin XuHong-Yuan Luo Zhi-Long Ye 《Journal of colloid and interface science》2012,388(1):201-208
In order to more easily separate TiO2 photocatalyst from the treated wastewater, TiO2 film was immobilized on the surface of activated carbon fibers (ACFs) by employing two kinds of coating procedures, dip-coating, and hydrothermal treatment. The effects of coating procedures on microstructure of TiO2-coated ACFs (TiO2/ACFs), such as morphology, porous property, crystal structure, and light absorption characteristics were investigated in detail. The adhesion property between TiO2 film and ACFs was evaluated by ultrasonic vibration, and the photocatalytic activity of TiO2/ACFs was tested by the photocatalytic decoloration of methylene blue solution. The results show that hydrothermal treatment presented many advantages to obtain high-performance TiO2/ACFs photocatalyst in comparison with dip-coating. Hydrothermal treatment could improve the binding property between TiO2 films and ACFs, which endowed the as-obtained TiO2/ACFs photocatalyst with improved reusable performance, and TiO2/ACFs synthesized by hydrothermal treatment presented higher photocatalytic activity. 相似文献
994.
Xiao-Feng Wu 《Tetrahedron letters》2012,53(45):6123-6126
A zinc-catalyzed oxidation of benzylic substrates has been developed. The corresponding carbonyl containing compounds have been produced in moderate to excellent yields. Both arenes and heteroarenes can be applied as substrates by using H2O2 as the oxidant. 相似文献
995.
《Analytical letters》2012,45(18):2892-2904
A spectrofluorimetric method has been developed for trace amount of aluminum(III) by using a novel Schiff base, N,N′-bis(salicylidene)-1,4-diaminobuthane (BUTAS), and 4-methyl-2-aminophenol (OAP). Since the aluminum complexes are generally fluorescent, aluminum(III) increases the fluorescence intensity of BUTAS-OAP by formation of Al-BUTAS-OAP complex. The fluorescence of the complex is measured at an excitation wavelength of 410 nm with an emission at 526 nm. Aluminum(III) can be detected within a concentration limit of 0.11–1.62 ppb and the lowest detection limit being 0.07 ppb. The proposed method was applied to diluted hemodialysis solution and spectrofluorimetric data was compared with data of standard pharmacopoeia method. 相似文献
996.
《Journal of Coordination Chemistry》2012,65(18):3188-3204
Four organic–inorganic crystals, [(HL1)2(ZnCl4)]·H2O (1) (L1?=?2-methylquinoline), [(HL1)2(CuCl4)] (2), [(HL2)2SnCl6] (3) (L2?=?6-bromobenzo[d]thiazol-2-amine), and [(HL3)FeCl4] (4) (L3?=?5,7-dimethyl-1,8-naphthyridine-2-amine), derived from N-containing aromatic Brønsted bases and metal(II) chlorides (zinc(II) chloride, copper(II) chloride dihydrate, tin(II) chloride dihydrate, and iron(III) chloride hexahydrate) were prepared at room temperature and characterized by IR, X-ray structure analysis, elemental analysis, and TG analysis. The crystals are built up by perchlorometallates (Zn, Cu, Sn, and Fe) associated with organic cations through multiple non-covalent associations. X-ray diffraction analysis reveals that 1 and 2 have 3-D network structures built from hydrogen bonds between the cations and chlorometallates. Water molecules play an important role in structure extension in 1. Anhydrous 3 and 4 produced from 2-aminoheterocyclic derivatives display 2-D sheet structures. Arrangements of anions and cations are dominated by shape and size of cations, and also by the different structures of the chlorometallates as well as non-bonding interactions in the crystal structures. Except for 1, the other compounds are thermally stable below 240°C. 相似文献
997.
《Analytical letters》2012,45(23-24):2207-2220
Abstract A new and highly sensitive method is presented for the spectrophotometric determination of four imidazoline derivatives: antazoline hydrochloride, tolazoline hydrochloride, xylometazoline hydrochloride and naphazoline nitrate. The method is based on the reaction of the corresponding drug base with 2,6 - dichlorophenol -indophenol (DGPIP) in chloroform to give a blue chromogen exhibiting a maximum at 588 - 603nm. The method could be applied for the quantitative determination of the above drugs either pure or in their pharmaceutical preparations (tablets and nasal drops). The results obtained are accurate and have good reproducibility. 相似文献
998.
Wine derives its economic value to a large extent from geographical origin, which has a significant impact on the quality of the wine. According to the food legislation, wines can be without geographical origin (table wine) and wines with origin. Wines with origin must have characteristics which are essential due to its region of production and must be produced, processed and prepared, exclusively within that region. 相似文献
999.
Two new β-carboline-type alkaloids,dichotomine K(1) and dichotomine L(2),were isolated from the roots of Chinese medicinal plant Stellaria dichotoma L.var.lanceolata Bge.Structures of 1 and 2 were determined on the basis of chemical and spectroscopic means. 相似文献
1000.
A simple and efficient synthesis of highly substituted pyrroles was achieved in water medium via multi-component strategy, using amine,DMAD/DEAD as well as phenacyl bromide catalyzed by β-CD.Utilizing this protocol various pyrrole derivatives were synthesized in good to excellent yields. 相似文献