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31.
A simple method has been developed for the simultaneous determination of N-butylscopolamine bromide and oxazepam in pharmaceutical formulations using first-order digital derivative spectrophotometry. Acetonitrile was selected as the solvent in which both compounds showed well-defined bands. Both analytes showed good stability in this solvent when solutions of the analytes were exposed to light and temperatures between 20 degrees and 80 degrees C. The simultaneous determination of both drugs was performed by the zero-crossing method at 226.0 and 257.0 nm for N-butylscopolamine and oxazepam, respectively. The linear range of determination was found to be 2.5 x 10(-7) to 8.0 x 10(-5) mol/L for N-butylscopolamine and 7.1 x 10(-8) to 8.0 x 10(-5) mol/L for oxazepam. A very good level of repeatability (relative standard deviation) of 0.2% was observed for N-butylscopolamine and oxazepam. The ingredients commonly found in pharmaceutical formulations do not interfere. The proposed method was applied to the determination of these drugs in pharmaceutical formulations (capsules). 相似文献
32.
Bitao Su Ke Wang Jie Bai Hongmei Mu Yongchun Tong Shixiong Min Shixiong She Ziqiang Lei 《Frontiers of Chemistry in China》2007,2(4):364-368
Fe3+-doped TiO2 composite nanoparticles with different doping amounts were successfully synthesized using sol-gel method and characterized
by X-ray diffraction (XRD), transmission electron microscopy (TEM) and ultravioletvisible spectroscopy (UV-Vis) diffuse reflectance
spectra (DRS). The photocatalytic degradation of methylene blue was used as a model reaction to evaluate the photocatalytic
activity of Fe3+/TiO2 nanoparticles under visible light irradiation. The influence of doping amount of Fe3+ (ω: 0.00%–3.00%) on photocatalytic activities of TiO2 was investigated. Results show that the size of Fe3+/TiO2 particles decreases with the increase of the amount of Fe3+ and their absorption spectra are broaden and absorption intensities are also increased. Doping Fe3+ can control the conversion of TiO2 from anatase to rutile. The doping amount of Fe3+ remarkably affects the activity of the catalyst, and the optimum efficiency occurs at about the doping amount of 0.3%. The
appropriate doping of Fe3+ can markedly increase the catalytic activity of TiO2 under visible light irradiation.
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Translated from Journal of Northwest Normal University (Natural Science), 2006, 42(6): 55–56 [译自: 西北师范大学学报(自然科学版)] 相似文献
33.
34.
铜在HOPG上电沉积过程的现场ECSTM研究 总被引:3,自引:1,他引:3
用自制的电化学扫描隧道显微镜(ECSTM)现场研究Cu在HOPG上的电沉积过程.结果表明Cu在HOPG上的电沉积为三维成核的过程.当电位较低或Cu2+离子浓度较低时,铜在本体金属生长主要沿着台阶方向.过电位较高时,铜的成核数目增加,沉积层的晶粒有所细化.同时,非现场ECSTM比较研究表明,STM针尖对针尖局部区域的电沉积起屏蔽作用,针尖所在区域Cu的沉积速度比其它区域明显减小 相似文献
35.
36.
The semiconductor properties of the interface TiO2/electrolyte in high organized porous oxide structures were analyzed by means of impedance spectroscopy near the flat band
potential. The impedance and capacitance studies performed on the as-anodized and thermally treated samples (anatase) indicate
the presence of a duplex structure formed by (1) the oxide at the bottom of the pores and (2) the walls of pores with different
donor densities and surface state concentrations. 相似文献
37.
现场表面拉曼光谱研究Fe-Mo合金诱导共沉积 总被引:1,自引:0,他引:1
现场表面拉曼光谱结果显示,在0.2mol·L-1Na2MoO4,pH=4.0的溶液中,电位正于0.5V(vsSCE)时只观察到多钼酸盐的拉曼峰(940、880和450cm-1).负于-0.5V时,出现中心位于730cm-1的宽峰.同时电极表面有蓝色膜生成.表明混合氧化态(MO(Ⅳ),MO(Ⅴ))氧化膜的形成.730cm-1的峰在-1.9V时仍然存在,说明氧化膜没有被进一步还原.在钼酸钠溶液中同时含有0.1mol·L-1FeSO4和0.2mol·L-1柠檬酸时,中间态氧化膜的拉曼峰的中心移到740cm-1.且峰强度随着电位从-1.3V负移到-1.9V而逐渐减弱并最终消失.电极表面沉积层呈银白色,说明由于Fe2 的存在,钼的中间态氧化膜的结构发生了变化,能够被进一步还原形成Fe-Mo合金,表现出诱导共沉积的特征. 相似文献
38.
Chaboy J Muñoz-Páez Díaz-Moreno S 《Chemistry (Weinheim an der Bergstrasse, Germany)》2001,7(5):1102-1108
An extensive study on the appearance of multi-electron features in the X-ray absorption spectra of several yttrium(III)-based compounds has been performed. The existence of a multi-electron transition of non-negligible intensity within the extended X-ray absorption fine structure (EXAFS) region of the Y K-edge spectra has been proven. The impact of such features in the EXAFS analysis is made evident for aqueous solutions of YBr3 x 6H2O in liquid and glassy states in the concentration range 0.005-2.0 M, in which this transition induces an overestimation in the coordination numbers derived from EXAFS. We have performed theoretical computation of cross-sections for the double-electron processes at the K-edge of both Y and Br. These computations have been applied to the experimental EXAFS K-edge spectra of both Y and Br in several solids and in aqueous solutions. While in the case of Y K-edge spectra the presence of such multi-electron transitions was seen to seriously affect the standard EXAFS analysis, its influence in the case of Br K-edge spectra was determined to be negligible. 相似文献
39.
The covalent conjugation of a 20-mer peptide belonging to the VP3 capsid protein of hepatitis A virus to the surface of preformed liposomes was investigated. Three different bonds (disulfide, thioether and amide) were established between the peptide sequence and liposomes bearing at their surface appropriate reactive groups. The effect of the relative concentration of the N-[4-(p-maleimidophenyl)butyryl]dipalmitoylphosphatidylethanolamine anchor in liposomes on stability during coupling of the peptide sequence was studied. The interaction of the three liposomal preparations with phospholipids in a biomembrane model system, monolayers at the air-water interface, is also reported. The results showed that although the peptides associate with liposomes in similar yields for the three strategies studied, differences can be observed when their interaction with phospholipid monolayers composed of dipalmitoylphosphatidylcholine is analysed. 相似文献
40.