谷光甘肽的毛细管电泳-Hg电极电化学检测

以毛细管悬汞电极为检测电极,设计制作了毛细管电泳-电化学检测系统.分析了谷胱甘肽在Hg电极上的电化学氧化,确定了谷胱甘肽的毛细管电泳-电化学检测的条件.谷光甘肽检测的线性浓度范围为1.0×10-7-8×10-5mol/L,检测限为1.5×10-8mol/L.     

聚甘氨酸修饰电极方波伏安法测定人体尿酸

利用方波伏安法研究了尿酸在聚甘氨酸修饰玻碳电极上的电化学氧化行为.结果表明:在0.01 mol/L磷酸盐缓冲液(pH=7)中,尿酸在+0.31 mv左右产生一个氧化峰,峰电流与尿酸在1.0×10-6—1.0×10-5mol/L浓度范围呈较好的线性关系,相关系数为0.9945.该方法可用于直接测定人体尿酸,回收率为95.5%-104.1%,相对标准偏差为1.4%.     

流动注射双安培法测定桑枝中桑色素

利用桑色素在经预阳极化处理的铂电极上的催化氧化和不可逆电对的双安培检测原理,建立流动注射双安培法直接检测桑色素的电化学新方法。使用经过恒电位预阳极化处理的双铂电极,在外加电位差为0V时,通过偶合桑色素在一支电极上的氧化和氧化铂在另一支电极上的还原两个不可逆电极过程,构成流动注射双安培检测体系。结果在0.1mol/L的NH3·H2O—NH4Cl(pH=11.0)缓冲液中,测得桑色素的氧化电流与其浓度在4.0×10-6～1.0×10-3mol/L范围内呈线性关系(r= 0.9991 ,n=14)。检出限为1.0×10-6mol/L。连续35次测定2.0×10-5mol/L桑色素,电流值RSD=1.7 %。     

聚苯胺掺杂乙醇胺修饰电极制备及其应用

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%.     

碳黑微电极快速测定果蔬中Vc含量

报道了用碳黑微电极快速测定Vc含量的一种新方法。实验结果表明.在pH为4.50的HAc-NaAc缓冲液中,Vc在该电极上的线性范围为6.0×10~(?)～2.0×10~5mol/L:最低检测限(3σ)为2.0×10~5mol/L。用这种电极测定Vc的含量,操作简单、数据准确、结果令人满意。     

亚铁氰化钾修饰碳黑微电极测定抗坏血酸

研究了抗坏血酸(AA)在亚铁氰化钾修饰碳黑微电极上的电化学行为。实验结果表明,在pH7．0的磷酸盐中,AA在该电极上的线性范围为2．0×10-6-4．0×10-3mol／L;检出限(3σ)为1．0×10-6mol／L。用这种电极测定抗坏血酸的含量,结果满意。     

极谱催化波法测定槲皮素

利用K2S2O8存在下槲皮素于-1.38V(vs.SCE)产生的极谱催化波,拟定了测定槲皮素的新方法。在0.02mol/L酒石酸-酒石酸钠(pH2.7)-1.0×10-2mol/LK2S2O8底液中,槲皮素催化波的峰电位为-1.38V(vs.SCE),其二阶导数峰电流与槲皮素浓度在1.0×10-7～2.0×10-6mol/L范围内呈线性关系(r=0.9984,n=6)。4.0×10-7mol/L槲皮素催化波的峰电流约为相应还原波峰电流的50倍。应用本方法直接测定良姜中的槲皮素,结果令人满意。     

碳糊修饰电极测定抗坏血酸的研究及应用

在1.0 mool/L KCl的介质中,采用邻苯二甲酸二正辛酯修饰碳糊电极测定抗坏血酸(AA),抗坏血酸的浓度在9.1×10-6-3.4×10-3mol/L范围内与峰电流呈线性关系,相关系数r=0.9994,检测限5.7×10-6mol/L,并且探讨了电极过程的特性.测定了市售抗坏血酸片和橙汁中抗坏血酸的含量,结果满意.     

8-羟基喹啉修饰玻碳电极微分脉冲溶出伏安法测定痕量铅

本文报道了一种用化学修饰电极测定水中铅离子的新方法.实验过程中,各种实验参数如电解质种类及酸度、修饰剂用量、富集电位和时间、扫描速度得到一定的优化.在pH=4.0的HAc-NaAc缓冲溶液中,铅离子与8-羟基喹啉生成螯合物富集在电极表面,然后在-1.0V被还原成零价的铅,在向阳极电位扫描的过程中,还原的铅被氧化而从电极表面溶出,出现阳极溶出峰,根据溶出峰电流可测定痕量铅离子.实验测得铅的线性范围为1×10-8mol/L至5×10-5mol/L,检测限为1×10-11mol/L.在5×10-7mol/LPb(Ⅱ)试液中,连续测定3次的标准偏差为6.3%.     

2,4-二羟基苯甲醛缩硫脲合镍(II)为中性载体的高氯酸根离子敏感电极的研究

研究了基于2,4-二羟基苯甲醛缩硫脲合镍(II)为载体的溶剂聚合膜阴离子敏感电极,该电极对高氯酸根离子(C1O-4)的电位响应具有优良的选择性和灵敏度。在pH=5.0的缓冲溶液中,电极电位呈近能斯特响应,线性响应范围为3×10-6—10-1mol/L,斜率为-52.8mV/dec,检测下限为6×10-7mol/L,该电极响应时间短,且具有良好的稳定性和重现性。     

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.