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《有机化学》2016,(9)
为进行抗小儿多动症原料药盐酸右哌甲酯的质量研究,合成了盐酸右哌甲酯及3个有关光学异构体.合成工作从2-氯吡啶2和苯乙腈3出发,经两步反应生成中间体5.5经加压氢化反应生成化合物6,化合物6经叔丁醇钾构型调整得化合物7a顺式消旋体,7a经D-二苯甲酰酒石酸拆分,甲酯化成盐,得化合物1a(盐酸右哌甲酯);7a经L-二苯甲酰酒石酸拆分,甲酯化成盐,得化合物1b;化合物6经乙酸乙酯打浆重结晶得化合物7b反式消旋体,7b经D-酒石酸拆分,甲酯化成盐,得化合物1c;7b经L-酒石酸拆分,甲酯化成盐,得化合物1d.合成的4个光学异构体经MS、NMR确证结构,HPLC确证化学和光学纯度,旋光仪确定旋光,盐酸右哌甲酯1a与化合物1d经X射线单晶衍射确定绝对构型,可作为盐酸右哌甲酯质量控制过程中的光学杂质对照品. 相似文献
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多壁碳纳米管修饰玻碳电极测定多巴酚丁胺的研究 总被引:4,自引:0,他引:4
研究了多巴酚丁胺在多壁碳纳米管修饰电极上的电化学行为,建立了一种直接测定多巴酚丁胺的电化学方法。在0.3mol·L-1H2SO4底液中,氧化峰电位为0.57V(vs.Ag/AgCl),峰电流与多巴酚丁胺的浓度在5.0×10-8~1.0×10-5mol·L-1范围内呈良好的线性关系。该法的检出限为3.0×10-8mol·L-1。平均回收率为99.15%。1.0×10-5mol·L-1多巴酚丁胺平行测定8次的标准偏差为4.8%。用拟定的方法测定了多巴酚丁胺注射液中多巴酚丁胺的含量,结果满意。 相似文献
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李硕 《理化检验(化学分册)》2006,42(3):166-168
在pH 7.6的三(羟乙基)胺(TEA)缓冲介质中,用单扫描示波极谱法测得由混配络合物Co2+·(DMGX)2·(NO2-)2所给出的灵敏还原极谱波,其峰电位在-1.07 V(vs.SCE)。峰电位与钴(Ⅱ)浓度在2.2×10-9-6.6×10-6mol·L-1之间呈线性关系(相关系数为0.999 7),其检出限为7.4×10-10mol·L-1Co2+。研究了电极反应的机理并证明该极谱波为由上文提到的三元混配络合物所给出的吸附催化波。 相似文献
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J. J. Berzas Nevado J. Rodríguez Flores 《Fresenius' Journal of Analytical Chemistry》1992,342(4-5):273-275
Summary A procedure based on the use of the Beckman Data Leader Software is proposed for resolving binary mixtures of electroactive analytes when their differential pulse polarographic peaks are overlapping without any separation step. The resolution is made by measuring in the selected zero-crossings of the first derivative differential pulse polarograms. For testing the procedure, two well-known systems were used, cadmium (II)-indium (III) and thallium (I)-lead (II) mixtures. The four metallic ions can be determined in diverse ratios with quantification limits lower than 10–7 mol/l. 相似文献
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Yuan Tian Trevor K. Decker Joshua S. McClellan Qinghao Wu Abraham De la Cruz Aaron R. Hawkins Daniel E. Austin 《Journal of the American Society for Mass Spectrometry》2018,29(7):1376-1385
The performance of miniaturized ion trap mass analyzers is limited, in part, by the accuracy with which electrodes can be fabricated and positioned relative to each other. Alignment of plates in a two-plate planar LIT is ideal to characterize misalignment effects, as it represents the simplest possible case, having only six degrees of freedom (DOF) (three translational and three rotational). High-precision motorized actuators were used to vary the alignment between the two ion trap plates in five DOFs—x, y, z, pitch, and yaw. A comparison between the experiment and previous simulations shows reasonable agreement. Pitch, or the degree to which the plates are parallel along the axial direction, has the largest and sharpest impact to resolving power, with resolving power dropping noticeably with pitch misalignment of a fraction of a degree. Lateral displacement (x) and yaw (rotation of one plate, but plates remain parallel) both have a strong impact on ion ejection efficiency, but little effect on resolving power. The effects of plate spacing (y-displacement) on both resolving power and ion ejection efficiency are attributable to higher-order terms in the trapping field. Varying the DC (axial) trapping potential can elucidate the effects where more misalignments in more than one DOF affect performance. Implications of these results for miniaturized ion traps are discussed. 相似文献
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Summary A method for densitometric determination of vitamins A, B1, B2, D3, and C separated by t. l. c. is described. A silica gel layer is used with a solvent system of acetone-methanol-benzene (128). The spots are evaluated by direct densitometric light emission measurements. Preliminary separation of the vitamins one from another or from other pharmaceuticals is not necessary. The accuracy of the method is about 6%. The accuracy for vitamin A is up to 12%.
Zusammenfassung Ein Verfahren zur Bestimmung der dünnschichtchromatographisch getrennten Vitamine A, B1, B2, D3 und C wurde beschrieben. Dazu dient eine Kieselgelschichte mit Aceton Methanol Benzol (128) als Lösungsmittel. Die Flecken werden densitometrisch gemessen. Eine vorhergehende Trennung der einzelnen Vitamine voneinander bzw. von anderen pharmazeutischen Begleitstoffen ist nicht nötig. Die Methode ist auf etwa 6% genau, für Vitamin A auf 12%.相似文献
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X射线衍射Rietveld分析和微反分析表明, A位含Dy的A2BO4型过渡金属稀土复合氧化物Dy0.5Sr1.5Mn1-xNixO4(0<=x<=1), 是空间群为I4/mmm的四方相K2NiFe型结构, A位和B位约有3%至7%的占位无序缺位。键价计算表明, B位Mn的平均价态在3.73至3.77之间, Ni在2.84至2.96之间。对CO氧化催化活性顺序为x=0.2>0.4>0.6>0.8>1.0。x=0.2的样品, 在空速5000h^-^1, 463K时, CO转化率达80%。 相似文献
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The separation of DNA by capillary electrophoresis using poly(ethylene oxide) (PEO) containing gold nanoparticles (GNPs) is presented. The impacts of PEO, GNPs, ethidium bromide (EtBr), and pH on the separation of double-stranded DNA have been carefully explored. Using a capillary dynamically coated with 5.0% poly(vinylpyrrolidone) and filled with 0.2% PEO containing 0.3 x GNPs (the viscosity less than 15 cP), we have demonstrated the separation of DNA markers V and VI within 5 min at pH 8.0 and 9.0. In terms of resolution and reproducibility, GNPs have a greater impact on the separation of DNA at pH 9.0. Resolution improvements for large DNA fragments (> 300 base pairs, bp) are greater than those for small ones in the presence of GNPs. It is important to point out that reproducibility is excellent (relative standard deviations for the migration times less than 0.5%) and thus no further dynamic coating is required in at least 20 consecutive runs in the presence of GNPs. Using 0.2% PEO (pH 9.0) containing 0.3 x GNPs, the separation of DNA fragments ranging in size from 21 to 23,130 bp was accomplished in 7 min. The results presented in this study show the advantage of PEO containing GNPs for DNA separation, including rapidity, high resolving power, excellent reproducibility, and ease of filling capillaries. 相似文献
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Multiphoton IR dissociation of SF6 (in a mixture with CH4) under nonequilibrium conditions of a compression shock formed by an intense, gas dynamically cooled, pulsed molecular beam impacting a solid surface was studied using the HF* luminescence detection ( 2.5 m) technique. The dependences of the HF* luminescence intensity on the distance x between the region in which molecules were excited and the surface and on the laser radiation frequency at different values of x were obtained. It was shown that, as the distance x decreased from 4 to 1.5 mm, the HF* luminescence intensity increased by more than an order of magnitude as compared to the case of excitation of molecules in an undisturbed flow, whereas the frequency dependences of luminescence intensity (SF6 dissociation yield) were broadened only insignificantly. 相似文献
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K. Gunji Z. Yoshida T. Adachi T. Komori 《Journal of Radioanalytical and Nuclear Chemistry》1987,118(3):225-233
Isotope dilution mass spectrometry using enriched isotope96Ru as a spike was applied to the determination of ruthenium as a fission product. Ruthenium in the solution was oxidized to RuO4 by Ce/IV/ and separated from coexisting metal elements by distillation. Silica-gel technique was employed to enhance ion current of ruthenium in the mass spectrometric measurement. The lower detection limit was 0.005 g ml–1 and the relative standard deviations /n=3/ for 1.2 and 0.05 g ml–1 of ruthenium were 0.2 and 0.5%, respectively. 相似文献
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Kaneto Uekama Yasuhide Horiuchi Masahiko Kikuchi Fumitoshi Hirayama Takanori Ijitsu Masao Ueno 《Journal of inclusion phenomena and macrocyclic chemistry》1988,6(2):167-174
Inclusion complexation of heptakis (2,6-di-O-methyl)--cyclodextrin (DM--CyD) with -tocopheryl acetate and -tocopheryl nicotinate in aqueous solution was studied by the solubility method. The aqueous solubilities of the esters were about 105 times increased by DM--CyD complexation. The phase-solubility diagram of the tocopheryl ester-DM--CyD systems showed a typicalA
p type, and the stability constants (K) of high-order complexes were estimated by analyzing the upward curvature of the diagrams. The solid complex of -tocopheryl nicotinate with DM--CyD in a molar ratio of 12 was prepared by the kneading method. The dissolution rate of the solid complex was much greater than that of the drug itself, and the rapidly dissolving form of -tocopheryl nicotinate, as an example, showed a markedly increased bioavailability (about 70-fold) after oral administration to fasted dogs. 相似文献
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Several substrates have been employed in different oscillatory systems. A serious limitation is the low solubility in water. This has been overcome by employing aqueous-organic mixed media in the iodate-system as well as the uncatalyzed and catalyzed [Ce(III) or Ferroin] systems. The present paper deals with the study of fifteen new substrates in the bromate-Mn(II) oscillatory system employing aqueous-organic mixed media.
. . , - , (Ce(III) ), . -Mn(II) - .相似文献
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N. M. Emanuel Z. K. Maizus V. G. Vinogradova 《Reaction Kinetics and Catalysis Letters》1977,6(2):119-124
A mechanism of the inhibiting action of Cu(II), Ni(II), Pb(II), Zn bis(N, N-dialkyldithiocarbamates) and Cu(II) bis (-thiopicolineanilides) in the AIBN initiated oxidation of ethylbenzene, styrene and nonene-1 is proposed. Inhibition is due to the deactivation of free radicals upon interaction with the chelate active center consisting of a metal with coordinated ligand atoms. As supported by the experimental data, the reaction occurs by an electron transfer mechanism.
-(N,N-) Cu(II), Ni(II), Pb(II), Zn -(-) Cu(II) , -1. . . .相似文献