首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
在0.1mol/LNaCl(pH=5.80)底液中,用单扫示波极谱法可得到一个灵敏的甲硝唑还原峰,峰电位为-0.58V(Vs.SCE),峰电流与甲硝唑浓度在4×10-8mol/L~1×10-4mol/L呈良好的线性关系(其线性相关系数r=0.9996),甲硝唑的检出限可达4×10-8mol/L.该法应用于模拟尿样和甲硝唑片剂质量含量的测定,结果令人满意.  相似文献   

2.
甲基绿与安乃近在pH 9.60的碱性介质中相互反应生成具有3个负吸收峰的离子缔合物,产生明显的褪色现象。最大褪色波长位于670nm,表观摩尔吸光系数为1.82×104 L/(mol·cm);次大褪色波长为424nm,表观摩尔吸光系数为1.50×104 L/(mol·cm),安乃近浓度为4.0×10-6~1.8×10-5 mol/L对670nm和4.0×10-6~1.4×10-5 mol/L对424nm光的吸光度与浓度关系遵从比尔定律,据此建立了以甲基绿为探针测定安乃近的吸收光谱法。该法用于实际样品中安乃近的测定,结果满意。  相似文献   

3.
在0.01 mol·L^-1的NaOH溶液中用玻碳电极研究甲硝唑的电化学性质,并用循环伏安法和示差脉冲伏安法对其含量进行测定。结果表明:甲硝唑在-0.631V和-0.731V处有一对明显的氧化还原峰,其还原峰电流与甲硝唑的浓度在8.0×10^-6-9.1×10^-4mol·L^-1(r=0.998)呈良好的线性关系,检出限为1.4×10^-7mol·L^-1。平均回收率98.9%,RSD=2.7%。甲硝唑在玻碳电极上的电化学行为受吸附控制。  相似文献   

4.
研究多壁碳纳米管修饰玻碳电极上核黄素的电化学行为,建立高灵敏度测定核黄素的电化学分析方法.在0.05mol/L磷酸缓冲液中(pH=7.0),核黄素在-410mV(vs.Ag/AgCl,3mol/L NaCl)和-446mV处出现一对氧化还原峰.电流与核黄素的浓度在1.0×10-6~1.0×10-4mol/L范围内呈良好的线性关系,检出限为3.2×10-7mol/L.对1.0×10-5mol/L核黄素连续11次测定,相对标准偏差为1.2%,分别制作7个修饰电极,相对标准偏差为4.7%.进行样品片剂核黄素的分析,结果满意.  相似文献   

5.
报道了吡啶铜与苯巴比妥络合物的极谱波.在0.1 mol/L的H2SO4溶液中,吡啶铜-苯巴比妥体系在-1780 mV处产生一个灵敏的极谱波.该吸附还原波的二阶导数峰电流与苯巴比妥浓度在6.0×10-7~2.0×10-3mol/L范围内呈线性关系,相关系数R=0.997;检出限为3.0×10-8mol/L.据此建立了测定苯巴比妥的新方法.此法已成功的用于巴比妥类药物的测定.  相似文献   

6.
利用循环伏安法制备银掺杂聚L-天冬氨酸化学修饰电极.用循环伏安法研究对氨基苯酚在该电极上的电化学行为,建立测定对氨基苯酚的新方法.在pH=5.5的磷酸盐缓冲溶液中,对氨基苯酚在银掺杂聚L-天冬氨酸修饰电极上产生一对灵敏的氧化还原峰,峰电位分别为Epa=203 mV,Epc=129 mV(相对Ag/AgCl电极).用循环伏安法(CV)进行测定,氧化峰峰电流与对氨基苯酚的浓度分别在8.00×10-7~1.00×10-4 mol/L和1.00×10-4~5.00×10-4 mol/L范围内呈线性,检出限为1.0×10-7 mol/L.对5.0×10-5 mol/L对氨基苯酚溶液平行测30次,其相对标准偏差为6.9%,用于废水中对氨基苯酚的测定,结果满意.  相似文献   

7.
报道了测定刺芒柄花素的单扫描示波极谱方法,在0.02mol/L的HAc ̄NaAc缓冲溶液(pH=5.35)中,刺芒柄花素在-1.34v(vs.SCE)处有一灵敏的二阶导数还原峰,峰电流与刺芒柄花素浓度在4.0×10-7~4.8×10-6mol/L范围内具有良好的线性关系(r=0.9955,n=6),检出限为2.0×10-7mol/L。用该方法测定刺芒柄花素,结果令人满意。  相似文献   

8.
利用VC的还原性,将Fe3+定量转化为Fe2+离子,产生的Fe2+与邻菲哆啉形成橘红色络合物,从而间接测定VC的含量。结果表明,络合物在510nm处有最大吸收峰,且显色物的浓度在2.0×10-6-5.0×10-5mol/L范围内与吸光度成正比,其相关系数R为0.9936,检出限为2.0×10-6mol/L,被测定样品的...  相似文献   

9.
在磷酸盐缓冲溶液(pH 7.4)中,利用循环伏安法研究了丝裂霉素的电化学行为.结果显示,丝裂霉素在玻碳电极上出现一对氧化还原峰,其中Epa=-0.520 V,Epc=-0.556 V.方波伏安峰电流与丝裂霉素的浓度在5×10-6~1.0×10-4mol/L之间呈良好的线性关系,检出限为1.5×10-6mol/L,可用于样品的测定.  相似文献   

10.
以(NH4)6Mo7O24·4H2O,MnSO4·H2O和(NH4)2S2O8为原料合成(NH4)6[MnMo9O32]·8H2O(八水合九钼锰酸铵),用紫外可见电子光谱分析法对该化合物进行表征;以490 nm为测定波长,测定浓度为8×10-4mol/L的(NH4)6[MnMo9O32]溶液与浓度分别为4×10-3、6×10-3、8×10-3、12×10-3 mol·L-1的酒石酸溶液进行氧化还原反应时的吸光度.以不同浓度的In(A-A∞)对T作图呈线型关系,确定氧化剂反应级数为一级反应.以不同浓度的Kobs对还原剂浓度作图,其图形也呈直线,确定还原剂反应级数也为一.  相似文献   

11.
《海外英语》2007,(5):44-45
It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,  相似文献   

12.
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/  相似文献   

13.
《海外英语》2007,(5):10-11
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?  相似文献   

14.
《海外英语》2007,(4):36
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.  相似文献   

15.
王菲 《华章》2007,(12):273-273
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.  相似文献   

16.
裴水妹 《华章》2007,(11):196
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.  相似文献   

17.
18.
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…  相似文献   

19.
《海外英语》2007,(4):8-9
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!  相似文献   

20.
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.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号