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1.
文章以环糊精及其衍生物为手性试剂,研究了血管扩张型降压药盐酸尼卡地平、尼莫地平和尼群地平手性对映体拆分方法.采用区带毛细管电泳模式,以高磺化环糊精(HS-CD)为手性识别试剂,考察了手性试剂的类型、浓度及缓冲溶液pH值等对分离度的影响,确定了拆分尼卡地平、尼莫地平和尼群地平手性对映体的最佳条件.结果表明盐酸尼卡地平在HS-γ-CD手性选择剂存在下对映体获得基线分离,尼莫地平和尼群地平分别在HS-β-CD和HS-α-CD手性选择剂存在下对映体获得部分分离,并对其分离机理进行了初步探讨.  相似文献   

2.
为分离生物碱氢溴酸山莨菪碱和盐酸阿托品手性对映体,探讨手性分离机理,在区带毛细管电泳模式下,以环糊精和环糊精衍生物为手性选择试剂,考察手性试剂的种类、浓度及缓冲溶液pH值和其它电泳条件对手性拆分效果的影响.结果显示,分离电压为-15kV,检测波长为200nm,缓冲溶液组成为含5%高磺化环糊精(HS-α,β,γ-CD)的50mmol·L。磷酸盐-三乙胺溶液(pH2.5)为最佳实验条件.其中HS-γ-CD基线拆分了山莨菪碱中2个手性碳原子的2对对映体,HS-β-CD分离了2种物质并基线拆分了山莨菪碱和盐酸阿托品中1个手性碳原子的1对对映体.因此,对于氨类碱性手性药物,高磺化环糊精比未衍生化环糊精和羟丙基环糊精的拆分效果好,而酸性条件下,高磺化环糊精与叔胺类物质间手性拆分作用除了空间匹配、氢键作用外,还存在静电引力作用.  相似文献   

3.
在40 mmol/L,PH值为2.5的磷酸二氢钠缓冲液中,分别以β-环糊精和HP-β-环糊精(取代度为5.5)及二者的混合物为手性添加剂对10种市售药物作了毛细管电泳分离,探讨了手性药物在环糊精中的嵌入型"包合络合作用",以及环糊精第二面上的羟基群在药物分离过程中的"边缘作用".  相似文献   

4.
HPLC手性流动相添加剂法拆分巴氯芬对映体   总被引:1,自引:0,他引:1  
建立了以羧甲基-β-环糊精为手性流动相添加剂,在反相液谱条件下拆分巴氯芬对映体的方法.研究了手性添加剂的种类及浓度、流动相组成、pH值及流速等因素对拆分的影响.流动相为甲醇、乙腈、水,体积比为90∶5∶5,其中含2.00g/L CM-β-CD,pH值5.95,流速0.60mL/min,检测波长231 nm,分离度为1.31.该方法简便、快速、相对偏差小.  相似文献   

5.
以外消旋色氨酸(DL-Trp)为模板分子,β-环糊精(β-CD)及其衍生物为单体构建手性环境,改变印迹体系和聚合方法合成了14种印迹聚合物(MIP1~14).采用SEM和N2吸附试验表征优化印迹聚合物MIP14的结构,通过吸附动力学曲线和吸附等温线模型探讨其吸附特性,并结合HPLC分析聚合物对DL-Trp的手性拆分能力.结果表明:MIP14为孔径分布较为均一的中孔材料,主要存在两类结合位点,符合二级动力学模型.MIP14具有良好的手性拆分能力,在含有6种芳香族氨基酸的复杂体系中可特异性拆分DL-Trp,拆分因子1.477,表明以环糊精衍生物直接印迹外消旋混合物来制备手性印迹材料是一条简便而可行的合成路线.  相似文献   

6.
提出了用毛细管区带电泳分离和检测肉碱对映体的方法。肉碱消旋体用4-溴苯甲酰甲基溴衍生化,并经选择性手性试剂——磺化β-环糊精和手性冠醚[(S,S)-l,7-bis(4-苯基-5-羟基-2-氧-3-氮苄基)-l,7-二氮杂-12-冠-4]协同作用后,可得到良好分离,并用紫外检测器检测,两异构体的检测下限约为80ng/mL。  相似文献   

7.
用β-环糊精修饰的膜成功地对1-甲基-6,7-二羟基-1,2,3,4-四氢异喹啉(Salsolinol)进行手性拆分.由高效液相色谱(HPLC)的分析结果可知,β-环糊精修饰的膜对Salsolinol具有手性选择性识别能力.通过一次膜循环的渗透实验,可使R-Salsolinol的比例由原来的0.87变为1.55.采用Gaussian 98程序研究了β-CD与R,S-Sal相互作用时的能量差别,并进行了理论计算,以探讨其拆分机理.  相似文献   

8.
以2-(11H-苯[a]咔唑)乙基氯甲酸酯(BCEC—Cl)作为柱前衍生试剂对氨基酸进行衍生,以三(羟甲基)氨基甲烷-磷酸(Tris—H3PO4)溶液作为缓冲溶液,β-环糊精(β—CD)为手性拆分试剂,十二烷基硫酸钠(SDS)为表面活性剂,采用胶束电动毛细管色谱模式考察并优化了氨基酸对映体的分离条件.结果实现了15种氨基酸对映体的拆分,结果令人满意.  相似文献   

9.
采用双相(O/W)识别体系对苯基琥珀酸对映体的萃取拆分过程进行动力学研究,对苯基琥珀对映体的萃取反应为一级反应;水相和有机相中使用的萃取剂分别为羟丙基-β-环糊精(HP-β-CD)以及L-酒石酸异丁酯(L-IBTA);考察搅拌速度、两相接触面积、水相中苯基琥珀酸对映体浓度、水相及有机相中萃取剂浓度、水相中pH对萃取初始速率的影响。在5℃时,双相识别体系萃取分离苯基琥珀酸的S-、R-型对映体的萃取速率常数分别为32.95×10 5m6.mol 2.s 1和16.18×10 5m6.mol 2.s 1。建立了双相识别体系萃取拆分苯基琥珀酸对映体过程的动力学模型。  相似文献   

10.
提出了用毛细管区带电泳分离和检测肉碱对映体的方法.肉碱消旋体用4-溴苯甲酰甲基溴衍生化,并经选择性手性试剂--磺化β-环糊精和手性冠醚[(S,S)-1,7-bis(4-苯基-5-羟基-2-氧-3-氮苄基)-1,7-二氮杂-12-冠-4]协同作用后,可得到良好分离,并用紫外检测器检测,两异构体的检测下限约为80 ng/mL.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

15.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

18.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

19.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

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