大孔吸附树脂预处理-HPLC法测定甘肃棘豆中苦马豆素含量

应用大孔吸附树脂为样品前处理技术,对甘肃棘豆中干扰苦马豆素含量测定的化合物进行选择性吸附除杂,以HPLC法测定样品中的苦马豆素含量.方法的平均回收率为92.81%(相对标准偏差为3.67%),日内和日间精密度分别为1.40%和3.98%,线性范围为0.022～0.730 mg/mL,方法检出限为0.010 mg/mL.方法可有效去除苦马豆素测定的干扰化合物,适用于甘肃棘豆中苦马豆素的含量测定.     

琥珀酰胆碱离子在水/邻硝基苯甲醚界面的伏安行为及其离子电极的研究

由于琥珀酰胆碱离子(Sch²⁺)在水(w)和邻硝基苯甲醚(NA)界面的传递半积分半微分循环伏安波与常规新极谱波的特性相似,测定了Δ_w^oφ_1/2、响应斜率、n和D_Sch^w2+.据此制备了以四苯硼琥珀酰胆碱[Sch(TPB)₂]为活性材料、邻硝基苯甲醚和邻苯二甲酸二丁酯(DBPH)为混合溶剂的Sch²⁺-PVC液膜电极.电极特性与Sch²⁺离子在w/NA界面传递所预示的结果相似.试验了电极对某些离子的选择性系数和回收率.     

电照相用近红外敏感有机光导材料

非银照相技术及其材料的发展极为迅速,日益得到广泛的应用.在电照相领域,近年发展起来的新一代带有计算机控制、数字扫描、激光成像的激光打印系统,具有分辨率高,印刷质量好,印刷速度快等特点,这种半导体激光打印系统的关键部件,是有机光导(OPC)鼓.     

The Solution of Dynamical Equation of Motion of IBM-Ⅱ in Continuous Variable Representation

In this article the solution of dynamical equation of motion of IBM-Ⅱ in continuous variable representation is discussed.With appropriate transformation and approximation,the on-phase part of system manifests the vibration-rotation mode and the off-phase part the 'scissor mode',ect.In the last section the energy spectrum of ¹⁵⁶Gd is calculated.The result can well reproduce the algebraic result of IBM-Ⅱ.     

Glyceric Prodrug of Ursodeoxycholic Acid (UDCA): Novozym 435-Catalyzed Synthesis of UDCA-Monoglyceride

Bile acids (BAs) are a family of steroids synthesized from cholesterol in the liver. Among bile acids, ursodeoxycholic acid (UDCA) is the drug of choice for treating primary biliary cirrhosis and dissolving cholesterol gallstones. The clinical effectiveness of UDCA includes its choleretic activity, the capability to inhibit hydrophobic bile acid absorption by the intestine under cholestatic conditions, reducing cholangiocyte injury, stimulation of impaired biliary output, and inhibition of hepatocyte apoptosis. Despite its clinical effectiveness, UDCA is poorly soluble in the gastro-duodeno-jejunal contents, and pharmacological doses of UDCA are not readily soluble in the stomach and intestine, resulting in incomplete absorption. Indeed, the solubility of 20 mg/L greatly limits the bioavailability of UDCA. Since the bioavailability of drug products plays a critical role in the design of oral administration dosages, we investigated the enzymatic esterification of UDCA as a strategy of hydrophilization. Therefore, we decided to enzymatically synthesize a glyceric ester of UDCA bile acid to produce a more water-soluble molecule. The esterification reactions between UDCA and glycerol were performed with an immobilized lipase B from Candida antarctica (Novozym 435) in solvent-free and solvent-assisted systems. The characterization of the UDCA-monoglyceride, enzymatically synthesized, has been performed by ¹H-NMR, ¹³C-NMR, COSY, HSQC, HMBC, IR, and MS spectroscopy.     

明胶酯化及酞酰化对于沉降性能的影响

酞酰化明胶作为中、低感光乳剂的沉降剂已经得到了广泛的应用。这个沉降剂的优点是沉降pH范围较窄,沉降速度较快,有增感作用,复溶容剔。它的主要缺点就是不适用于氨法高感乳剂。究其原因,主要是由于PA改性明胶的等电点比较低。     

Correlation potentials for the He atom and the hydrogen molecule: A comparison between the correlation factor approach and DFT correlation energy functionals

Two points about correlation potentials have been dealt with in this article. The first one is related to the shape of some of the most representative correlation potentials applied to the ground state of the He atom. It is shown here that both LDA and two-body density correlation potentials compare well with that obtained through the quantum chemistry definition of correlation energy. This is an interesting result because, in previous works, it had been shown that none of the correlation potentials compared well with the Kohn–Sham one. The gradient-corrected correlation potentials exhibit a very different behavior to that of both exact potentials (quantum chemistry and Kohn–Sham ones). The other question posed here refers to how a reference to the two-body density must modify DFT functionals for the correlation energy, when a multideterminant wave function is needed. This question has been addressed by analyzing the variation of correlation potentials as the bond length of the H₂ molecule increases. The results show that an external reference to the two-body density qualitatively improves DFT correlation potentials and also that only those functionals explicitly depending on two-body density can give the quantitative correct trends. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 67: 143–156, 1998     

溴代靛红异构体含量的同时测定

采用紫外二阶导数分光光度法测定常山酮合成工艺中同分异构体6-溴靛红和4-溴靛红的含量。4-溴靛红测定的线性范围2～80mg/L,相对标准偏差0．178％,回收率99．9％～100．1％;6-溴靛红测定的线性范围2～60mg/L,相对标准偏差0．091％,回收率98．7％～100.1％。该法简便、快捷、准确、灵敏。     

中性微乳液介质增敏鲁米诺电化学发光研究

磷酸盐缓冲的中性溴化十六烷基三甲基铵-正戊醇-正庚烷微乳液介质体系对鲁米诺的电化学发光有显著的增敏作用,本文对此增敏作用进行了研究,并在此介质体系中采用电化学发光淬灭法测定了生物活性分子褪黑素,此法可用于测定脑白金胶囊中的褪黑素。