共查询到19条相似文献,搜索用时 78 毫秒
1.
大黄游离羟基蒽醌的TG—DTA和XRD谱图特征分析 总被引:1,自引:0,他引:1
中药大黄属蓼科植物,性寒味苦,是中医临床常用药物,具有攻坚破积、活血化瘀、泻火凉血、清热解毒及抗菌、抗炎、调节免疫、抗肿瘤、止血和保健等作用[1]. 相似文献
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反相高效液相色谱法测定大黄药材中游离及结合型蒽醌类衍生物的含量 总被引:25,自引:0,他引:25
建立了同时测定大黄药材中蒽醌类衍生物含量的RP HPLC法。色谱柱为HypersilC1 8柱 (2 5 0mm×4 6mmi.d .,1 0 μm) ,流动相为甲醇 乙腈 水 (3∶5∶2 ,磷酸调pH 2 .8) ,流速为 1 .0mL min ,柱温为 2 5℃ ,检测波长为 2 2 5nm。在此色谱条件下 ,各组分在 2 0min内均得到良好分离。平均回收率为 98.83 %~ 1 0 0 .9% ;相对标准偏差 0 .68%~ 1 .5 8%。 相似文献
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在模拟人体生理条件下,利用紫外光谱法、荧光光谱法和同步荧光光谱法结合研究三种羟基蒽醌类药物(1,2-二羟基蒽醌、1,4-二羟基蒽醌和1,8-二羟基蒽醌)与溶菌酶(LYSO)相互作用机制,并探讨其构效关系。紫外结果初步显示,三种羟基蒽醌类药物与LYSO发生相互作用。荧光结果进一步证实三种羟基蒽醌类药物均与LYSO发生结合,且对LYSO的荧光猝灭机制均为静态猝灭并伴随有非辐射能量转移。三种羟基蒽醌类药物与LYSO均存在一个结合位点,它们与LYSO形成1∶1复合物,在303K下,结合常数K分别为8.47×105、4.88×105和5.43×105L·mol-1,结合距离r分别为5.83、5.12和5.14nm,与溶菌酶作用后焓变分别为-41.2、-87.6和-39.0 kJ·mol-1,熵变分别为-22.4、-180和-19.1 J·mol-1·K-1。三种羟基蒽醌类药物与LYSO的作用力均为范德华力和氢键,且作用强弱不同,其顺序为:1,2-二羟基蒽醌1,8-二羟基蒽醌1,4-二羟基蒽醌。同步荧光法结果表明三种羟基蒽醌类药物与LYSO相互作用后均导致LYSO构象发生改变。研究结果表明,蒽醌环上羟基位置的不同对羟基蒽醌类药物与溶菌酶结合强弱有较大程度的影响。 相似文献
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通过对23个羟基蒽醌衍生物的质子核磁共振研究, 观察了不同取代类型羟基的化学位移范围;讨论了酚羟基乙酰化对芳环质子的化学位移影响, 为羟基取代位置的确定及芳环质子谱线归属提供了某种判据.此外, 还用HMO 法探讨了各类取代羟基的氢键强度及羰基迫位仅有一个羟基的内氢键强度与给予原子电荷密度的关系.本文报道一系列新型冠醚N,N'-双取代-1,7-二氧杂-12-冠-4(1~6), N,N' -双取代-1, 7-二氮杂-15冠-5(7~10) 及N,N'-双取代-1,10-二氮杂-18-冠-6(11~14)的质谱. 借助联动扫描和去焦技术对它们的开裂机理作了详细探讨. 相似文献
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测量了1,4-羟基蒽醌及其氘化物的红外光谱,用NRCC程序进行了振动分析,由于同时考虑了分子内与分子间的氢键,统一处理面内与面外振动,计算结果优于文献报道,并纠正了一些错误归属。 相似文献
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钢渣中游离氧化镁含量的测定 总被引:1,自引:0,他引:1
研究和提出了以硝酸铵-乙醇作为提取剂提取活性氧化镁(即游离氧化镁)的分析方法。通过正交实验,选取了最佳的提取条件。样品平行测定的相对标准偏差在0.51%~2.13%之间,回收率实验结果为98.2%~99.0%,表明该实验的精密度和准确度均较好。采用硝酸铵-乙醇作为提取剂提取游离氧化镁的分析方法,实现了钢渣中游离氧化镁的快速、准确测定,为钢渣的回收再利用提供了依据。 相似文献
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大黄蒽醌衍生物的高效液相色谱法测定及在家兔体内的药代动力学研究 总被引:5,自引:0,他引:5
建立了家兔血浆中大黄蒽醌衍生物的高效液相色谱测定方法,并用于含大黄单 复方制剂中蒽醌衍生物在家兔体内的药代动力学研究。血样经处理后,在μ-Bondapak C 18柱上分析,流动相为甲醇-乙腈-0.2 mol/L磷酸二氢钠溶液(体积比为27∶35.5∶37.5),磷酸调pH 2.8,检测波长为225 nm。在此色谱条件下,各蒽醌衍生物与内标1,8-二羟基蒽醌的分离度符合要求,血浆内源性成分无干扰。两种制剂灌胃后的血药浓度-时间曲线符合二室模型, 二者的AUC无显著性差异。该法灵敏 准确,适用于含大黄的 相似文献
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1,5-二硝基蒽醌电化学还原制备──1,5-二氨基-4,8-二羟基蒽醌的研究(英文) 总被引:4,自引:0,他引:4
采用循环伏安法、稳态极化曲线法和恒电位电解法相结合的实验手段,研究了1,5-二硝基蒽醌(1,5-DNA)在硫酸溶液中、汞齐化铜电极上阴极还原制备1,5-二氨基-4,8-二羟基蒽醌(1,5-DA-4,8-DHA)的电化学反应性能.结果表明:在12.75mol/LH2SO4和140℃温度下,1,5-DNA在汞齐化铜阴极表面上具有反应物强吸附和不可逆随后化学反应的特征.电解最后的产物经红外光谱测定为1,5-二氨基-4,8-二羟基蒽醌,平均电流效率为78%,产率为72%.1,5-DNA直接电化学还原的行为与电极材料、酸浓度、添加剂、反应物浓度等有关. 相似文献
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Li Ming ZHANG Xia LI Yu Jie DAI 《中国化学快报》2006,17(5):699-702
Rhubarb is an important Chinese traditional medicine and its genins such as aloe-emodin have been widely used in the field of antibacterial, antivirus, antitumor and antibacterial immunity1,2. Chrysophanol and physcion are the effective components for dec… 相似文献
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Poly(3-hydroxybutyrate)/Cloisite30B (PHB/30B) nanocomposites were prepared by solution-intercalation method. The influence of 30B content on the thermal stability of PHB was investigated. With the addition of 3 wt. % of 30B the highest thermal stability of PHB was achieved. The kinetic analysis of the non-isothermal degradation was performed using the isoconversional Friedman method and invariant kinetic parameters method. 相似文献
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Stability studies on nifedipine tablets using thermogravimetry and differential scanning calorimetry
R. O. C. Filho P. I. B. M. Franco E. C. Conceição M. I. G. Leles 《Journal of Thermal Analysis and Calorimetry》2008,93(2):381-385
A formulation of nifedipine tablets was prepared in the present research. The tablets were conditioned in amber-colored glass
containers and placed in a climatized room at 40°C and relative humidity of 75% for 180 days. Differential scanning calorimetry
(DSC) and thermogravimetry (TG) were used in order to evaluate the thermal properties of nifedipine, the excipients and two
well-known nifedipine degradation products. The results demonstrated that there is no evidence on the interaction between
nifedipine and excipients, or degradation products. 相似文献
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The decomposition behaviour of dolomite samples has been carried out by simultaneous DTA-TG experiments. Dolomite samples
could be classified broadly into two categories as regular and iron-bearing dolomites based on DTA decomposition temperatures.
The mass% FeO of all the dolomite samples was identified by DTA and the results are confirmed by atomic absorption spectrophotometer
experiments.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Mineral oil type lubricating oils have an important role in reducing engine wear. But after some period, depending on the
oil quality, oil replacement is needed since the oil loses its properties. In this paper, an engine oil was tested in a 1300
cc engine car and the change of the thermal stability of the collected portions of oil at different usage periods were experimented
by TG/DTG and DSC techniques. Results show that, as usage period increases lubricating oil contains more of the light components
that distill at low temperatures. The increase in the peak maximum temperature, Tmax, of the DTG, as usage period increases, proposes that the molecular mass of the oil increase, which presumably changes the
viscosity characteristics. Moreover as the usage period increases some residue type components, which only can be destroyed
at very high temperatures, are produced in oil phase.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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K. Kulesza K. Pielichowski Z. Kowalski 《Journal of Thermal Analysis and Calorimetry》2006,83(2):475-478
The thermal decomposition
of iminodiacetic, oxydiacetic, and thiodiacetic acids in helium atmosphere
has been studied by means of thermogravimetry (TG), differential thermal analysis
(DTA) and temperature-programmed pyrolysis directly coupled with mass spectrometry
(TPPy-MS). Evolved gas analysis (EGA) profiles of iminodiacetic and oxydiacetic
acids were obtained and compared with TG and DTA profiles.
The decomposition
of iminodiacetic acid forms water, CO, CO2, CH3CN,
HCN and some hydrocarbons. After water evolution a cyclic anhydride is formed,
as well as for oxydiacetic acid. Thiodiacetic acid vaporizes without decomposition. 相似文献
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Brown L. D. Ray A. S. Thomas P. S. Guerbois J. P. 《Journal of Thermal Analysis and Calorimetry》2002,68(1):31-36
Naturally occurring opals from three different regions in Australia were studied for their thermal characteristics. All the
opals showed initial expansion followed by contraction in thermomechanical analysis (TMA) although the temperature at which
the change from expansion to contraction occurred depended on their provenance. Thermogravimetric analysis (TG) revealed different
rates and temperatures of dehydration for these opals. A general correlation between the temperature at which there was a
zero thermal expansion and that of the maximum rate of dehydration was observed. A dehydration–sintering mechanism is proposed
with the effect of sintering being more pronounced following total dehydration.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献