用固相萃取和微柱高效液相色谱法快速测定枸杞样品中的类胡萝卜素

研究了固相萃取富集和预分离,微柱高效液相色谱快速测定枸杞样品中类胡萝卜素的方法;枸杞样品中的类胡萝卜素用Waters Sep-Pak C18固相萃取小柱预分离,然后以Waters XterraTMRP18(1.0×50 mm,2.5μm)微柱为固定相,甲醇-四氢呋喃(80:20,V/V)为流动相分离,用二极管矩阵检测器检测,检测波长为450 nm,枸杞样品中的几种类胡萝卜素在5 min内可达到基线分离。方法标准回收率为95~103%,RSD为1.9~2.6%。用该方法测定了几种枸杞样品中的类胡萝卜素,结果令人满意。     

微柱高效液相色谱法测定阿奇霉素含量

研究了用固相萃取富集和预分离,微柱高效液相色谱快速测定阿奇霉素的方法;样品中的阿奇霉素用W atersX terraTMRP18反相固相萃取小柱预分离和富集,然后以W aters X terraTMRP18(1.0×50 mm,2.5 mm)微柱为固定相,四氢吡咯-醋酸缓冲溶液(pH 11.0)和乙腈(50∶50,v/v)为流动相分离,用二极管矩阵检测器检测,检测波长为215 nm,样品中的阿奇霉素在5.0 m in内可达到基线分离.方法标准回收率为90%~101%,RSD为0.38%~2.8%.用该方法测定了注射液和尿样品中的阿奇霉素,结果令人满意.     

微柱高效液相色谱法测定岩白菜素含量研究

研究了用微柱高效液相色谱法测定岩陀及复方岩白菜素片中岩白菜素的含量.样品中岩白菜素用甲醇超声振荡提取,提取液通过Sep-Pak-C18固相萃取小柱过滤收集,然后以WatersXterraTMRP18(1.0×50mm,2.5μm)微柱为固定相,22%的甲醇为流动相分离,岩白菜素在0.99min即可达到基线分离,用紫外二极管矩阵检测器检测.方法标准回收率为98.1%～104%,相对标准偏差为1.7%～2.2%.此方法可快速、准确的测定岩白菜样品中岩白菜素的含量.     

固相萃取-高效液相色谱法测定杜鹃中的几类黄酮

通过固相萃取-高效液相色谱法测定了杜鹃中的几类黄酮.用80%甲醇回流提取杜鹃样品中的黄酮,提取液经W aters Sep-Park-C18固相萃取小柱预分离,以W aters X terraTMC18(150×4.6 mm,φ3.5μm)色谱柱为固定相,甲醇-水为流动相梯度洗脱,杜鹃中的几类黄酮得以分离和测定.新方法标准回收率95%~105%,RSD为1.6%~2.5%.     

微柱高效液相色谱法测定贯叶连翘中的芸香苷

研究了用微柱高效液相色谱法测定贯叶连翘中芸香苷.样品中的芸香苷用80%甲醇加热回流提取,以WatersXterraTMRP18(1 0×30mm,2 5μm)色谱微柱为固定相,1%的醋酸和甲醇为流动相,在该色谱条件下,样品芸香苷在1 0min内可达到基线分离,用紫外二极管矩阵检测器检测,方法可用于贯叶连翘中的芸香苷的测定.     

微柱高效液相色谱法测定Cu(HQ)2和HQ

研究了用微柱高效液相色谱法测定8-羟基喹啉铜中的8-羟基喹啉(HQ)和8-羟基喹啉铜[Cu(HQ)2]的方法,8-羟基喹啉铜样品用甲醇溶解,然后以WatersXterraTMRP18(1.0×50mm,2.5μm)微柱为固定相,60%的甲醇(内含0.05moL/LpH值为4.0的醋酸-醋酸钠缓冲盐)为流动相分离,用紫外二极管矩阵检测器检测测定,方法标准回收率在99-102%,相对标准偏差在0.58-0.65%之间,结果满意.     

匀浆法提取-高效液相色谱法测定金银花中的绿原酸

分别用3种前处理方法对金银花中的绿原酸进行提取,用高效液相色谱法进行检测.结果表明,用匀浆法提取所需时间明显少于热回流提取法和超声波提取法,采用80%的甲醇匀浆法提取金银花中的绿原酸,提取液中的绿原酸以W aters X terra RP18(3.9 mm×150 mm,5μm)色谱柱为固定相,1%醋酸为流动相,梯度洗脱,流速为0.8 mL/m in,检测波长345 nm.在该色谱条件下,绿原酸质量浓度在5.0~200μg/mL内成良好的线性关系,样品平均加标回收率为118%,相对标准偏差(RSD)为4.5%(n=6),结果令人满意.     

杭白菊中井冈霉素A的固相萃取

建立杭白菊中井冈霉素A的固相萃取的方法。比较不同溶剂对目标农药的提取效率,其中采用甲醇-水(8∶2)提取时,井冈霉素A的平均回收率最好,平均回收率在89.53%-93.73%。比较不同萃取方式的净化效率,其中用C18-HLB串联小柱固相萃取井冈霉素A的回收率效果最好,为89.43%-92.60%。选择0.5 m L乙腈进行洗脱,发现第3次洗脱后回收率稳定,在90.05%-98.04%。用建立的方法对胎菊和朵菊样品进行添加回收率试验,杭白菊鲜样及干样中井冈霉素A的添加回收率在83.02%-89.93%之间,相对标准偏差(RSD)为0.57%-2.95%。     

地下水中多菌灵残留的SPE-HPLC分析方法

建立了检测地下水中多菌灵残留量的固相萃取-高效液相色谱法.样品经C18固相萃取小柱富集净化后,以甲醇-(水+氨水)为流动相,高效液相色谱-紫外检测器检测,外标法定量.在0.01~1.0 mg/L质量浓度范围内,线性相关系数0.999 9,最低检出限为0.003 4 mg/L.添加质量浓度为0.01,0.05,0.18 mg/L,回收率在95.3%~97.8%之间,相对标准偏差(RSD)为3.09%~4.18%.方法应用在实际样品分析中可行,适用于地下水样中痕量有机物的检测.     

动态微波辅助萃取与高效液相色谱联用测定金银花中的绿原酸

通过流动注射的方法将动态微波辅助萃取与高效液相色谱相连接, 用于测定金银花中的绿原酸. 萃取过程在一个循环体系中完成, 萃取后, 通过采样环采集到的20 μL样品被流动相载带到色谱系统进行分离检测. 在最佳实验条件下得到的检出限和测定下限分别为0.25和0.83 μg/mL, 日内和日间精密度(RSD)分别为3.4%和4.1%, 平均加标回收率为98.1%.     

Markedness and its Interpretation in Language Use

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.     

Features of Women's language

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

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-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

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