顶空毛细管气相色谱法测定盐酸拉贝洛尔中有机残留量

目的:建立了盐酸拉贝洛尔中丙酮、乙酸乙酯、甲醇、异丙醇、乙醇、二氧六环残留量的测定方法.方法:使用DB-WAX柱(30 m×0.32 mm,0.5 μm),以高纯氮气为载气,以岛津2010气相色谱仪为检测器;程序升温,初始温度40 ℃,保持5 min,以5 ℃/min升温至80 ℃;50 ℃/min升温至200 ℃,保持5.5 min.进样口温度为200 ℃,检测器温度为250 ℃.结果:丙酮、乙酸乙酯、甲醇、异丙醇、乙醇、二氧六环具有良好的线性;相对标准偏差均小于7.5%,平均回收率99.53%~106.77%.结论:此方法简单、准确,灵敏度高,可用于检测盐酸拉贝洛尔中的丙酮、乙酸乙酯、甲醇、异丙醇、乙醇和二氧六环的残留量的测定.     

土壤改良剂中脂肪酸二乙醇酰胺的HPLC分析

应用反相高效液相色谱法(HPLC),采用C18键合相色谱柱和紫外检测器,对土壤改良剂中的有效成分脂肪酸二乙醇酰胺进行定量分析.该方法快速准确,标准偏差为0.021%,变异系数为1.3%,回收率为98.68%-102.93%.     

GC法测定蔬菜水果中有机氯农药残留量

目的：建立测定蔬菜水果中有机氯农药残留量的气相色谱法.方法：采用DB-1弹性石英毛细管柱（30m×0.25mm×0.25μm）,进样口温度260℃;检测器温度280℃;柱升温程序：初始温度150℃,以10℃/min升至210℃保持10min,以20℃/min升至240℃保持5min.结果：12种有机氯农药的线性范围为10～400ng·mL^-1.结论：该方法简便、快速、准确,适用于蔬菜水果中有机氯农药残留量的测定.     

气相色谱法测定青蒿提取物中二十八烷醇和二十六烷醇的含量

建立青蒿素提取物中二十八烷醇、二十六烷醇含量检测的气相色谱方法.采用毛细管色谱柱BD-17(30m×530μm×1.0μm);FID检测器;气化室温度269℃;柱温为一级程序升温(155℃-2min-10℃·mim-1-262℃-12min);载气高纯氮42.0mL/min;空气410.0mL/min;氢气38.0mL/min.平均回收率:二十八烷醇为100.16%(n=5),RSD为0.91%;二十六烷醇为98.5%(n=5),RSD为1.23%.该方法准确、灵敏、重现性好,可适用于提取分离二十八烷醇、二十六烷醇时质量控制和含量检测.     

HPLC-ELSD法测定壳寡糖酸降解液中氨基葡萄糖含量探索

目的:探索并建立一种简便、有效、准确测定壳寡糖酸降解液中氨基葡萄糖盐酸盐含量的方法.方法:采用Shodex NH2P-50 4E色谱柱(4.6×250 mm,5 μ m),以乙腈:水(梯度洗脱)为流动相,流速为1.0 mL/min,柱温为35℃;使用蒸发光散射检测器,载气流速为1.5L/min,漂移管温度为60℃;进样...     

顶空气相色谱法检测三七总皂苷中的大孔树脂残留物

采用顶空进样毛细管气相色谱法,色谱柱为HP-INNOWAX毛细管柱(30 m×0.32 mm×0.5 μm);柱温(程序升温):60℃维持16 min,再以每分钟20℃的升温速率升至200 ℃,维持2 min;进样口温度:240℃;FID检测器温度:300℃;25%N,N-二甲基乙酰胺为溶解介质,载气为氮气,测定三七总皂苷中正己烷、苯、甲苯、对二甲苯、邻二甲苯、苯乙烯、1,2-二乙基苯7种大孔树脂有机溶剂残留量.结果本法线性关系良好,r=0.9957～0.9999,精密度RSDs均小于7.0%.7种溶剂的平均回收率为95.59%～101.34%,其RSDs在1.10～1.91%.该方法操作简便快速,灵敏度高,准确度好,可作为三七总皂苷中大孔树脂有机溶剂残留量的测定方法.     

GC测定风油精中薄荷脑含量的实验教学设计

设计用GC测定风油精中薄荷脑含量的药物分析实验.用乙酸乙酯为溶剂提取样品,HP25毛细管柱(530μm X 30 m,1μm)及氢火焰离子化检测器;载气为高纯氮,栽气流速2 mL/min,进样口和检测器温度均为250 ℃.标准曲线方程为A=0.008C-0.0286(R2=0.9999,n=5),在0.375～6g/L线性关系良好.高(6g/L)、中(1.5g/L)、低(0.375g/L)3个浓度的日内、日间变异均＜3%;3个浓度的加样回收率依次为99.10%、104.52%、97.30%;最低检测浓度为0.25g/L.筛选出了合适的处理样品的溶剂和最佳的GC分离条件,考查了方法的精密度和回收率,最终确定了稳定的实验条件.     

生普洱茶与熟普洱茶中咖啡因含量的HPLC分析

采用高效液相色谱法对生普洱与熟普洱茶中咖啡因的含量进行测定.色谱柱为Kromasil C18;流动相:水-甲醇-乙酸-二甲基酰胺(70:30:0.05:0.25,V/V);色谱柱温:25℃;进样量:5μL;检测器:紫外检测器;扫描波长:210~400 nm;检测波长:274 nm.方法变异系数小于3.96%,回收率为90.62%~103.8%.生普洱茶和熟普洱茶咖啡因含量分别为19.92 mg/g和28.58 mg/g.     

相转移催化下的合成安息香缩合反应研究

以PEG-6000为相转移催化剂,VB1为催化剂,合成了二苯羟乙酮(安息香),找出了最佳反应条件:PEG-6000的用量为1.5 g、反应温度为50℃、回流时间80 m in、氢氧化钠浓度10%(5 m l),反应生成物产率达70.8%-80.2%,重现性达100%。     

两种植物中喜树碱含量的检测和比较

选择乙醇浸提超声波法处理样品,高效液相色谱(HPLC)检测,二极管阵列检测器(DAD),Diamonsil^(TM) C_(18)(4.6×150 mm,5μm)柱,流动相为V_(甲醇):V_水=55:45,流速为0.80 mL·min(TM) C_(18)(4.6×150 mm,5μm)柱,流动相为V_(甲醇):V_水=55:45,流速为0.80 mL·min^(-1),进样量为10μL,柱温为35℃,检测波长为254 nm定量检测.结果表明:马比木中喜树碱的含量高于喜树果,实验结果为药物活性成分提取原料选择提供理论参考.     

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?     

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…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

The Reader Response Approach to Teaching of English Literature

During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context.