荧光光度法测定药物中的多巴胺

本文建立了用1,3-环己二酮-甲醛作为荧光衍生试剂测定多巴胺的方法。多巴胺与1,3-环已二酮-甲醛反应生成一种强荧光物质。其最大激发波长是393nm,最大发射波长是450nm。多巴胺浓度在10～40μg/ml范围内与相对荧光强度存在线性关系,线性方程为C=0．1732F-29．6873,线性相关系数为0．9993,相对标准偏差为2．5％,检出限为18ng/ml,回收率为97．9-101．7％。实验了pH值,温度,放置时间,干扰离子等对测定的影响。此法可用于注射液中多巴胺含量的测定。     

Eu(Ⅲ)-La(Ⅲ)-四环素协同荧光增敏体系测定四环素(英文)

在系统地研究Eu（Ⅲ）－La（Ⅲ）－TC协同荧光增敏体系的基础上，提出了一个测定微量四环素的荧光分析新方法．体系的激发波长和发射波长分别为396nm和616nm，线性范围为2×10－9～4×10－7mol·L－1．该法能用于测定尿液和血浆中的微量四环素．     

高效液相色谱法测定木瓜中维生素C的含量

建立了一种高效液相色谱测定木瓜中维生素C含量的方法．采用0．1％的草酸作为提取剂,色谱中采用Zorbax SB～C18色谱柱,0．1％草酸水作流动相,流速1．0m/min,紫外检测器检测波长261nm．维生素C在20—100μg／mL内有良好的线性关系,线性回归方程为A=73．0542C＋50．6898,相关系数为0．9998,方法回收率为98．81％～102．45％,相对标准偏差等于0．861％．所用测定方法简便、快速,能准确测定木瓜中维生素C的含量．     

荧光猝灭法快速测定环境样品中的邻苯二甲酸二丁酯

用荧光光谱法研究了邻苯二甲酸二丁酯（DBP）与荧光素（HFIn）的荧光性质,建立了一种简单、快速、灵敏测定邻苯二甲酸二丁酯的新方法。结果表明：在pH=6.0的NaAc-HAc缓冲溶液中,加入邻苯二甲酸二丁酯使荧光素的荧光猝灭,体系的激发波长和发射波长分别为487nm和532nm。HFIn的荧光强度差值与DBP的含量在0.2～8.0mg/L范围内呈良好线性关系,检出限为0.092mg/L。应用于水样和一次性塑料袋中痕量邻苯二甲酸二丁酯的测定,结果满意,并进行了加标回收实验。     

赣南脐橙中维生素C的测定研究

采用紫外分光光度法测定了赣南脐橙中的维生素C含量,探讨了波长、静置时间等相干实验条件.结果表明,最大吸收波长243 nm,宜静置时间40 min,最佳pH=10,得到的回归方程ΔA=0.05496C+0.00651,相关系数r=0.9999,维生素C浓度在1.00—12.0μg/mL范围内与紫外吸收值呈良好的线性关系,利用此方法测定样品中维生素C含量最低检出限0.014μg/mL,回收率98.4%—101.0%之间,相对标准偏差RSD<5%.     

Eu（Ⅲ）-La（Ⅲ）-四环素协同荧光增敏体系测定四环素

在系统地研究Eu(Ⅱ)-La(Ⅲ)-TC协同荧光增敏体系的基础上；提出了一个测定微量四环素的荧光分析新方法．体系的激发波长和发射波长分别为396nm和616nm，线性范围为2×10^-9～4×10^-9mol·L^-1，该法能用于测定尿液和血浆中的微量四环素。     

荧光法快速检测水果和蔬菜中的抗坏血酸

维生素C(抗坏血酸)经Cu2+氧化为脱氢抗坏血酸,在一定条件下与邻苯二胺反应生成具有荧光的物质.基于此,建立了一种新的测定维生素C的荧光分析法.实验中对氧化剂Cu2+及邻苯二胺的用量、缓冲液介质等进行了优化,在优化条件下,维生素C的浓度在0.05～5.00 μg/mL与其对应荧光强度呈良好的线性关系,相关系数R2=0.998 7;检出限为0.03 μg/mL;对3个不同浓度的样品进行加标回收实验,其回收率为88.91％ ～92.25％;对1.0μg/mL的样品测定3次,测定结果的相对标准偏差为1.98％.将该法用于西红柿、青椒等水果及蔬菜中维生素C含量的测定,结果令人满意.     

荧光法测定食品包装材料中的双酚A

建立了用十六烷基三甲基溴化铵做增敏剂,使双酚A的荧光强度增强,从而定量检测食品包装材料中双酚A含量的方法。在缓冲溶液的pH=6,在波长λex／hem=240／335nm时,测定双酚A的荧光强度。检出限为10．1μg／L,线性范围为0．1—6mg／L。该法检测灵敏、准确、快速简便。     

波长扫描在鉴别荧光铁载体与荧光素中的应用

荧光铁载体与荧光素在外观上极其相似,溶液均为透明的黄绿色,并且在紫外线的照射下均可以产生荧光．而两者的结构和分子组成相差较大,导致了在光谱吸收方面的差异．本文采用波长扫描的方法对其进行了检测,发现荧光铁载体在400nm波长处有一特异的最大光谱吸收峰,而荧光素的最大吸收峰则在490nm波长处．因此波长扫描的方法可用于鉴别荧光铁载体与荧光素．     

阿魏酸的荧光光谱与荧光量子产率

在酸性条件下,阿魏酸荧光强度随pH值的升高而增大,荧光峰的最大激发和发射波长分别为310 nm和415 nm。在碱性条件下,最大激发波长和发射波长红移到350 nm和460 nm处。随着pH值的升高,其荧光强度逐渐增大,当pH值大于10.0时,其荧光强度达到最大值且趋于稳定。阿魏酸的荧光光谱随pH值的变化是由于其分子中羧基和羟基质子的离解。以硫酸奎宁为参比,测得阿魏酸水溶液的荧光量子产率为0.006 1。     

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.     

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.     

团图为数的图中的闭团贯数

Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F.     

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.