银掺杂聚L-天冬氨酸修饰电极测定对氨基苯酚

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.     

线性扫描伏安法测定维生素B2

运用循环伏安法(CV)、线性扫描伏安法(LSV)等方法研究维生素B2在多壁碳纳米管修饰电极上的电化学行为,建立一种直接测定维生素B2的电化学分析方法.与裸玻碳电极相比,多壁碳纳米管修饰电极显示出很好的催化作用,维生素B2在修饰电极上得到一对灵敏的氧化还原峰(Epa=-0.222 V,Epc=-0.317 V),且氧化还原峰电流显著增强.在优化实验条件下,还原峰电流与维生素B2浓度在3.0×10-6～2.0×10-5mol·L-1有良好的线性关系,检出限为1.0×10-6mol·L-1.对1.0×105mol·L-1维生素B2溶液平行测定10次的相对标准偏差(RSD)为4.2%.用此方法测定维生素B2片中维生素B2的含量,结果令人满意.     

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%.     

碳纳米管修饰碳糊电极吸附溶出伏安法测定铜

制备了羧基化碳纳米管修饰碳糊电极(MWCNT/CPE),并研究了Cu(II)-SPAPT络合物在该电极上的吸附伏安行为,建立了一种测定痕量铜的新方法.采用二阶导数线性扫描溶出伏安法进行分析.结果表明:在0.1 mol/L的HAc-NaAc(pH=4.0)中,于-400 mV处搅拌富集一定时间,从-400～600 mV范围内以250 mV/s的扫描速度线性扫描,络合物吸附在MWCNT/CPE表面,于66 mV(vs.SCE)处产生一灵敏的阳极溶出峰,其峰电流与Cu(Ⅱ)浓度在4×10-11 mol/L-8×10-9 mol/L和8×10-9 mol/L-1×10-7 mol/L范围内分两段呈良好的线性关系,检出限(S/N=3)为2.2×10-11 mol/L(富集时间240 s).同时,探讨了电极反应机理.该方法操作简便、灵敏度高,应用于人发中铜含量的测定,结果满意.     

槲皮素修饰电极对抗坏血酸的催化氧化研究

用卡拉胶将槲皮素固定在玻碳电极表面,槲皮素修饰电极在pH=2.0～6.0的磷酸氢二钠-柠檬酸缓冲溶液中出现准可逆的氧化还原反应,探讨了其电化学机理.槲皮素修饰电极对抗坏血酸具有电催化作用.催化电流与抗坏血酸的浓度在3.1×10-5mol·L-1～2.0×10～mol·L-1范围内呈良好的线性关系,其检测下限达1.5×10-5mol·L-1.     

L-半胱氨酸和银分层修饰电极的制备及对多巴胺的测定

用循环伏安法制备L-半胱氨酸和银分层修饰电极,用阻抗谱对分层修饰电极进行表征.研究修饰电极上多巴胺的电化学行为,建立差分脉冲法测定痕量多巴胺的新方法.结果表明,在扫描速率为100 m V/s,p H3.0的磷酸盐缓冲溶液中,多巴胺在L-半胱氨酸和银分层修饰电极上产生一对明显的氧化还原峰,峰电位分别为Epa=0.452 V,Epc=0.404 V.用差分脉冲法测定时,峰电流与多巴胺浓度分别在2.50×10-7~7.50×10-6mol/L和7.50×10-6~1.00×10-4mol/L呈线性关系,检出限为7.5×10-8mol/L.用于香蕉中多巴胺的测定,结果满意.     

对苯二酚、邻苯二酚的快速同时测定

提出了一快速、简便同时测定对苯二酚和邻苯二酚的方法.在浓度为0.1 mol.L-1的HAc-NaAc(pH=5.6)缓冲液中,用玻碳电极(GC)测定对苯二酚、邻苯二酚的还原峰电流,并采用半微分技术进行峰分离,同时添加表面活性剂提高检测的灵敏度,实现了二者的同时测定.结果表明:在1.2×10-6～1.0×10-4 mol.L-1范围内,对苯二酚的半微分电流与其浓度呈线性关系;邻苯二酚的线性范围为8.2×10-7～1.0×10-4 mol.L-1,二者的检测限分别为3.6×10-7和2.4×10-7 mol.L-1.将此方法用于模拟废水中苯二酚的检测,回收率为97%～104%.     

焦性没食子酸的循环伏安测定及其电化学行为研究

在0.05mol·L-1柠檬酸-柠檬酸钠(pH 3.0)的底液中,采用循环伏安法测定焦性没食子酸,得到一良好的氧化峰,峰电位EP= 0.40V,峰电流IP与焦性没食子酸的浓度在7.930×10-6～1.031×10-4mol·L-1范围内成线性关系.相关系数r=0.9992,检出限为7.930×10-6mol·L-1.采用本法测定工业焦性没食子酸中焦性没食子酸的含量,平均回收率在101.0%.并且研究了焦性没食子酸在玻碳电极上的电化学行为,结果表明焦性没食子酸的电极过程具有扩散性和不可逆性.     

铜掺杂聚L-赖氨酸膜修饰电极的制备及其用于橙汁饮品中抗坏血酸的测定

利用循环伏安法制备铜掺杂聚L-赖氨酸修饰玻碳电极,并对抗坏血酸的电化学行为进行研究。建立用循环伏安法测定抗坏血酸的新方法。在p H=2.5的磷酸盐缓冲溶液中,扫描速率为180 m V/s,抗坏血酸在修饰电极上产生一灵敏的氧化峰,响应峰电位为0.364 V,抗坏血酸的浓度峰电流在8.0×10~(-5)~8.0×10~(-3)mol/L的范围内有良好的线性关系,检出限为8.0×10~(-7)mol/L。对橙汁饮品进行测定,结果满意。     

碳纳米管修饰电极上核黄素电化学行为的研究及其分析应用

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.     

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.