共查询到20条相似文献，搜索用时 140 毫秒
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气相色谱法测定水环境中酚的研究 总被引：1，自引：0，他引：1
本文建立了毛细管气相色谱法测定水质中酚含量的方法 ,对测试条件进行了系统的讨论。该方法的相关系数为 0 .9995,检出限围 4 .0× 1 0 -5μg/ml,相对标准偏差为 1 .1 %～ 6.6% ,加标回收率为 89.1 %～ 96.0 % ,该法与国标法比较 ,其测定结果无显著性差异 ( P>0 .2 0 )。该法灵敏度高 ,测定结果准确可靠 ,操作简便。 相似文献
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采用化学聚合的方法(循环伏安法)制备聚苯胺掺杂乙醇胺的修饰电极,并研究了该修饰电极的电化学性质和在抗坏血酸等物质存在下测定人体尿酸的电化学分析方法.研究发现该修饰电极在0.02 mol/L磷酸盐缓冲液(pH=5.86)介质中,聚苯胺掺杂乙醇胺的玻碳修饰电极对尿酸具有明显的电化学响应.在2.5×l0-6~1.0×10-5mol/L内,尿酸浓度C与峰电流Ip成线性关系,相关系数r=0.9932.利用该法直接测定人体尿样中尿酸的含量,测定结果的相对标准偏差为3.63%,回收率为98.7%~100.77%. 相似文献
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本试验采用高效毛细管电泳法,测定了柴胡中丁香酚的含量.丁香酚在0.038～1 mg·mL-1的范围内与峰面积积分值线性关系良好,回归方程Y =11465.43X+159.64(r=0.9926),平均回收率为97.3%,RSD=1.87%(n=6).该法简便、准确、重复性好,有助于柴胡质量控制方法的研究. 相似文献
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对铁观音茶和茶茎原花青素的含量进行测定.采用超声提取法,90%乙醇做提取剂,用1%的香草醛-盐酸溶液作为显色剂,对样品中的原花青素含量进行测定.用原花青素标准品得到线性回归方程为:A=8.301 3×C-0.047 3,相关系数R=0.999 6,原花青素的浓度在0.020～0.120 mg/mL范围内,吸光度A与浓度C呈良好线性关系.方法的加标回收率为96.5%～101.5%,变异系数为0.01%,该方法的准确度与精密度均较高,可按标准曲线法进行定量分析. 相似文献
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利用苯酚-硫酸法对葡萄酒中的多糖含量进行了测定,同时比较了葡萄酒不同前处理的实验结果.苯酚-硫酸法建立的标准曲线为A=0.072 6C+0.001 6,相关系数r=0.999 8,回收率在99.17%～100.3%之间.葡萄酒前处理时,用醋酸铅做沉淀剂,在70℃下沉淀20 min后过滤测定.结果表明:沉淀处理有助于排除杂质干扰,有效减少稀释倍数. 相似文献
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采用凯氏定氮法和光谱法分析测定五味子不同部位蛋白质的含量.对传统的凯氏定氮法的催化剂进行了改进,加快了消化速度,缩短了分析时间.光谱分析方法的回收率为92.10%~102.35%,变异系数为0.12%,结果表明该方法简便、快速、准确可行. 相似文献
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李丽 《遵义师范学院学报》2007,9(2):58-60
在NaOH介质中,山奈酚对KMnO4-luminol体系的化学发光有增敏作用,据此采用流动注射技术,建立测定山奈酚的化学发光新方法。该法测定山奈酚的检出限为1.2×10-8g.mL-1,线性范围为8×10-8～1×10-5g.mL-1,对1×10-6g.mL-1山奈酚进行了11次平行测定,其RSD为3.8%。考察了影响该体系发光强度的因素,该法用于合成样品中山奈酚的测定获得满意结果。 相似文献
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用红外光谱内标法(K3[Fe(CN)6)]·6H2O为内标物)测定了红霉素肠溶片中红霉素的含量.实验表明:混合物红外光谱中红霉素的测量峰(1714.6cm-1)和K3[Fe(CN)6)]·6H2O的内标峰(2119.0cm-1)的峰高比(y=h i/h s)与两者质量比(x=m i/m s)有良好的线性关系,其线性回归方程为y=0.2642x-0.0579,相关系数R2=0.9973.据此测得红霉素肠溶片中红霉素的含量为标示量的101%,相对标准偏差为0.51%,加标回收率分别为96.8%101.9%.该方法无需分离提取,简便,快速,成本低,测定结果准确,特别适合批量检测和药品质量的快筛,有应用价值. 相似文献
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电位滴定法测定茶叶中茶多酚的含量 总被引：1，自引：0，他引：1
该文建立了电位滴定法测定茶叶中茶多酚含量的定量分析方法.以高锰酸钾为氧化剂,在硫酸强酸性介质中,用待测样品试液进行电位滴定,用一阶微分法确定待测样品试液的滴定终点体积,方法的RSD为4.07%(n=5),平均回收率为99.6%,该法准确、简便,可用于茶叶中茶多酚含量的测定. 相似文献
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《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
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罗艳萍 《读与写:教育教学刊》2008,5(6)
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. 相似文献
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《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
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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
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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
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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Richard Denner 《海外英语》2007,(4):14-15
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. 相似文献