薄叶卷柏总黄酮的纯化工艺研究

建立了一种大孔树脂分离纯化薄叶卷柏中总黄酮的工艺。通过静态、动态吸附及解吸试验,以吸附率和解吸率为主要指标考察各因素对纯化工艺的影响。优选的纯化工艺为:以D-101型大孔树脂为吸附剂,上样液质量浓度3.910mg·m L-1,上样流速为2BV/h,最佳上样量为19.55mg·m L-1,水洗至洗脱液无色,再以6BV50%乙醇洗脱总黄酮,洗脱流速为3BV/h。所得提取物中总黄酮纯度达70.55%,收率为87.04%。该优选工艺稳定可行,适用于薄叶卷柏总黄酮的纯化分离。     

金莲花总黄酮纯化研究

目的:利用正交试验,优选金莲花总黄酮的纯化方法.方法:以总黄酮含量为考查指标,选择大孔吸附树脂、乙醇浓度、上样量、洗脱速度和吸附时间五个实验因素,采用L16(45)正交实验表进行实验,筛选出总黄酮的最佳纯化工艺.结果:影响金莲花总黄酮含量的主要因素是乙醇浓度,其次是大孔吸附树脂的类型.按最佳方案纯化,总黄酮含量可达到69.1%.结论:最佳纯化方法为:采用大孔吸附树脂D-101,以50%乙醇洗脱,最佳上样量10mL,吸附时间20min,洗脱速度2.0 mL·min-1.     

大孔树脂纯化银杏叶中总黄酮的工艺研究

目的：研究不同型号大孔树脂纯化银杏叶总黄酮的工艺条件及参数。方法以静态饱和吸附量、洗脱量、静态洗脱率考察指标,比较了5种大孔树脂,以总黄酮的含量为指标对树脂吸附工艺条件进行了筛选。结果所比较的8种大孔吸附树脂中,D101树脂具有最佳的吸附及洗脱参数,在上样液浓度为4.0 mg·mL-1条件下,上样体积为35mL,用70%的乙醇作为洗脱剂,洗脱流速为3 mL·min-1,得到总黄酮含量为56.89%。结论 D101树脂综合性能较好,可有效地用于银杏叶黄酮的分离富集。     

淫羊藿总黄酮常压提取分离工艺研究

通过水煮提取及萃取方法提取出淫羊藿总黄酮,常压下利用聚酰胺、硅胶等进行柱层析分离提纯淫羊藿总黄酮．最佳工艺为800ml水回流两次。每次两小时,而后,用100ml 95％乙醇回流两小时．     

大孔吸附树脂分离纯化异黄芪甲苷的工艺

以异黄芪皂苷含量为指标,高效液相色谱-蒸发光散射检测器（HPLC-ELSD）为检测方法,系统研究了D101大孔吸附树脂分离纯化异黄芪甲苷的吸附性能和洗脱参数.当上样液浓度为1 g.mL-1,上样体积（mL）∶树脂量（g）为3∶1时,D101大孔吸附树脂可100%吸附异黄芪甲苷;流速为5.0BV/h,4BV体积的蒸馏水、30%乙醇、50%乙醇和70%乙醇梯度洗脱时,70%乙醇洗脱液中异黄芪皂苷洗脱率达93.14%.实验结果表明D101大孔吸附树脂对异黄芪甲苷有较好的吸附和解吸性能,适合于异黄芪皂苷的分离纯化,可为大规模制备异黄芪甲苷提供参考.     

淫羊藿常压提取分离总黄酮含量的测定

在淫羊藿常压提取淫羊藿总黄酮过程中,利用高效液相色谱法对分离提取的淫羊藿总黄酮含量进行了测定.根据液相色谱图可知,乙酸乙酯萃取所得产品杂峰少,产品纯.     

巫山淫羊藿光合生理日变化及其主要影响因子研究

采用Li-6400光合作用测定系统测定巫山淫羊藿叶片光合生理日变化,并用SPSS19.0相关性分析探讨了巫山淫羊藿光合生理特征参数及其环境影响因子的相互关系,为巫山淫羊藿资源的种植栽培提供理论参考依据.结果显示:巫山淫羊藿叶片的最大净光合速率为5.28μmol CO_2·m^(-2)·s(-2)·s^(-1);其净光合速率、气孔导度和蒸腾速率的日变化均呈双峰曲线,影响净光合速率的主要环境因子是相对空气湿度.水分利用效率日变化与净光合速率显著正相关,与胞间CO_2浓度负相关.     

淫羊藿中黄酮类化合物分离鉴定的研究进展

文中综述了淫羊藿中黄酮类化合物分离及鉴定方法的研究进展,为淫羊藿有效成分的开发提供依据.采用水提法提取后,在黄酮类化合物的多种分离方法之中,溶剂萃取法具有价廉、易得等特点.而采用与碱的显色反应来鉴定淫羊藿有效成分黄酮的存在最为简单、方便.     

大孔树脂纯化蓝莓果渣花青素的研究

目的:筛选分离纯化蓝莓果渣花青素的最佳树脂,优化纯化蓝莓果渣花青素的工艺条件。方法:比较AB-8、D101两种大孔树脂对蓝莓果渣花青素的吸附解吸效果,研究了AB-8大孔树脂对蓝莓果渣花青素的吸附解吸条件。结果:AB-8大孔树脂是纯化蓝莓果渣花青素较好树脂,其对蓝莓果渣花青素吸附解吸平衡时间均为4 h;吸附最适温度60℃、样液稀释4倍、p H 3.0、吸附流速1 m L/min时吸附能力最佳,乙醇浓度60%、p H 3.0、解吸流速1 m L/min时解吸能力最佳。结论:该工艺得到的花青素产品为紫黑色粉末,色价为16.90,是未纯化样品色价的5倍。     

葛根异黄酮的分离与纯化

本实验通过单因素试验和正交试验探讨了葛根异黄酮的最佳浸取工艺，并对大孔树脂对葛根异黄酮纯化进行了详细研究。试验结果表明：浸提时，在温度为70℃的条件下，用8倍于(v／w)葛根量浓度为50％的乙醇，浸提2．5h，葛根异黄酮浸取率最高；对六种商品化大孔树脂吸附纯化葛根异黄酮的性能进行对比筛选，发现AB-8树脂最适合葛根异黄酮的纯化。实验结果表明，洗脱剂乙醇浓度为70％(v／v)，工作液流速为2BV／h，浸提浓缩液pH值为5时，采用AB-8大孔吸附树脂串联柱对葛根异黄酮进行纯化，其效果最优，产品的收率和纯度都较高。     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.