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 共查询到19条相似文献,搜索用时 125 毫秒
1.
库仑滴定法测定烟叶提取物中茄尼醇   总被引:16,自引:0,他引:16  
本文提出用库仑滴定法测定茄尼醇。以含有1mol·L-1KBr的78%(V/V)醋酸溶液为介质,以5mA恒电流为电解电流,对布尼醇进行库仑滴定,用双铂电极电流法指示滴定终点,得到满意结果.方法简便、准确,不需要标准溶液,不需要昂贵仪器。  相似文献   

2.
倒数示波计时电位法的研究: 新线路的研制及应用   总被引:2,自引:0,他引:2  
朱俊杰  郑建斌  沈岚  高鸿  卜海之 《化学学报》1993,51(10):999-1004
本文研制了获得倒数示波计时电位图的新线路, 并加上电流反馈装置。这套装置具有灵敏度高、稳定性好等特点, 应用此线路, 我们用新的方法进行了峰电位的测量、痕量物质的分析及药品含量测定。  相似文献   

3.
对插型阵列微带电极的制作及其电化学特性研究   总被引:1,自引:0,他引:1  
用微电子光刻方法制作了对插型阵微带电极(IDA),并通过SEM对IDA电极进行了表征,将微Ag/AgCl参比电极和微铂丝对电极固定在IDA电极附近,构成了微电解池,考察了该电极的循环伏安及计时电流特性,并用微带电极的扩散理论和Cottrell 公式对IDA电极的准稳太电流进行了处理,指出了它们之间产生偏差的原因,研究了IDA电极的“发生-收集”效应,测定了该电极的屏蔽因子、反馈因子和收集效率。  相似文献   

4.
用脉冲波交流电流作为极化电流的微分简易示波伏安法   总被引:7,自引:1,他引:7  
用脉冲波交流电流作为极化电流的微分简易示波伏安法郑建斌,赵明仁,朱小红,苏玉祥(西北大学化学系电分析化学研究所,西安,710069)关键词示波分析,微分简易示波伏安法,脉冲波交流电流经典示波计时电位法在微量乃至于痕量组分的直接测定方面的应用一直进展缓...  相似文献   

5.
电流反馈的高次微分示波极谱滴定法   总被引:5,自引:0,他引:5  
在高次微分示波极谱滴定法中,利用电流反馈技术对充电电流进行补偿,可使高次微分示波极谱图上去板剂切口的灵敏度进一步提高。当切口电位处的|dCd/dE|或|d2C4/dE2|值相对较小时,电流反馈的作用就较明显。利用电流反馈高次微分示波极谱滴定法以氨羧络合剂滴定了Cd2+、Ni2+、Co2+、Pb2+、Zn2+,用Zn2+返滴定法测定了Al-Ni合金中的Ni,终点变化敏锐。  相似文献   

6.
循环伏安法研究硝基药物的β—环糊精包含络合物   总被引:3,自引:0,他引:3  
本文用悬汞电极循环伏安法,研究了甲硝唑、氯霉素、对硝基苯酚和对硝基苯甲酸等药物的伏安性质,用“电流法“测定了药物与β-CD生成包络物的Kf值,并讨论其作用及稳定性。  相似文献   

7.
本文介绍用双工作电极串联式的薄层电池,结合阳极溶出伏安法,用上游工作电极作富集-溶出电极;下游工作电极作收集电极,记录下游工作电极的收集电流。本法具有溶出法和薄层伏安法的优点,可消除电位扫描引入的电容电流,以及吸附电流、杂质电流的干扰,有效地提高了信噪比,提高了测定的灵敏度和分辨率。  相似文献   

8.
本文推导了聚苯胺膜电极上计时电流法和计时库仑法理论公式,并成功地进行了验证,理论和实验结果相符合,还测定了扩散系数,结果与文献报道相一致。  相似文献   

9.
用线扫溶出伏安法和循环伏安法研究了鸟嘌呤在玻碳电极上的电化学行为,鸟嘌呤的阳极锋电流与其浓度在1×10-7-5×10-4mol/L范围内有良好线性关系。讨论了实验条件,建立了测定鸟嘌呤的新分析方法,应用于生物样品中鸟嘌呤的测定,结果满意.  相似文献   

10.
报道了纳米级超微带电极的制作方法,并分别用扫描隧道电镜、扫描电镜和光电子能谱对电极表面进行表征、用循环伏安法、计时电流法考察了电极的性能、将半微柱的扩散模型用于描述50nm以上的超微带电极,结果表明,超微带电极的带宽对电流变化影响不大,而非法拉第电流却正比于电极面积.用超微带电极可提高信噪比,测定亚铁氰化钾检测限可达5.0×10~(-7)mol/L.  相似文献   

11.
张兰  陈国南  方禹之 《化学学报》2004,62(10):975-978
依据毛细管区带电泳的特性,推导出在不同pH条件下,有效淌度的倒数(1/μep)与缓冲溶液中氢离子浓度([H^ ])成线性关系,进而建立了用毛细管电泳-电化学检测法测定四种生物碱:苯异丙胺、苯丙醇胺、麻黄碱和甲基麻黄碱电离常数的线性模型和测定方法,测得的pKa值,与紫外分光光度法测定值及文献值比较,结果令人满意.可望在药物离解常数测定的应用中得到推广.  相似文献   

12.
Capillary electrophoretic estimation of apparent binding constants (Kapp) for naproxen, salbutamol, indomethacine and procaine with beta-cyclodextrin is presented. While with naproxen and indomethacine this approach was straightforward and gave well compatible results by three different linearization plots (double reciprocal, x reciprocal and y reciprocal), with salbutamol a higher value than reported for the electromigration estimation of this magnitude was obtained (a fourfold increase). This difference is ascribed to the fact that the measurements were done in the acid region (while the reported values were obtained at higher pH values). As a matter of fact the values of Kapp, reported in this communication for salbutamol comply better with the value of Kapp (69.3) obtained by the solubility method.  相似文献   

13.
《Analytical letters》2012,45(8):1333-1340
A Raman spectroscopy-based approach was developed for the rapid determination of lactose in milk using crystal violet as an internal standard. The crystal violet peak at 1173 reciprocal centimeters did not interfere with the lactose peak at 1085 reciprocal centimeters; therefore, crystal violet can be used to quantify lactose in milk. This developed method allowed the determination of lactose from 0.028–0.1 mole per liter, with a limit of detection of 0.019 mole per liter. The results revealed that Raman spectroscopy is a simple and rapid method for the determination of lactose in milk.  相似文献   

14.
本文应用二氢叶酸(DHFA)和辅酶Ⅱ(NADPH)的荧光性质,建立了二氢叶酸还原酶(DHFR)活力测定的反应体系,并对酸度等反应条件进行了优化。在该体系中,用双倒数作图法分别测定了二氢叶酸还原酶对二氢叶酸和辅酶Ⅱ的表观米氏常数。将所建立的体系应用于氨甲喋呤,甲氧苄氨嘧啶等已知抑制剂的抑制率的测定,结果满意。  相似文献   

15.
Zabuye Saline Lake, Tibet, China, is unrivalled in the world for its very high salinity, in particular, for the very high concentration of ions of lithium, potassium, and boron in the brine. It belongs to alkaline and carbonate-borate-type salt lake. As a part of the study on phase equilibrium of the 6component subsystem Li+, Na+, K+/C1-, CO2-3, B4O2-7-H2O of the brine system, a study on the reciprocal quaternary system Li+, K+/C1-, CO32-H2O at 298 K was done with isothermal dissolution equilibrium method in the present work. The phase equilibrium of the reciprocal quaternary system Li+,K+/C1, CO2-3-H2O at 298 K was studied with isothermal dissolution method in this work. The physicochemistry properties of the corresponding equilibrium solutions such as densities, viscosities, refractive index, conductivities and pH value were determined. The dried salt diagram of the system consists of four crystallization fields (KC1, Li2CO3, LiCI·H2O, K2CO3·3/2H2O) and five isothermal solubility curves.There are no double slat or solid solution found. Pitzer′s model of the electrolyte solution theory was used for parameterization from the results of solubility determination for subsystems and the prediction of solubilities for the reciprocal quaternary system was made. The solubility data of the experiment are in agreement with those calculated.  相似文献   

16.
微分倒数示波计时电位滴定   总被引:5,自引:0,他引:5  
倒数示波计时电位滴定~[1]是最近提出的一种电滴定方法,它把(dE/dt)-E曲线上的切口转变为(dE/dt)~(-1)-E曲线上的峰,从而大大抑制了充电电流,提高了滴定分析的灵敏度.本文报道了微分倒数示波计时电位滴定,即对(dE/dt)~(-1)-E曲线进行一次或二次微分处理,利用示波图上去极剂峰的出现与消失指示终点,使滴定终点更易观察.  相似文献   

17.
A quaternary reciprocal system of fluorides, chlorides, and bromides of lithium and potassium was partitioned into simplexes by a geometric method and by a graph method. Phase transformations and chemical reactions in the boundary ternary reciprocal systems were described. A conversion line was experimentally studied, and information on crystallizing phases within the composition prism of the Li,K‖F,Cl,Br system was obtained and confirmed by X-ray powder diffraction data. An immiscibility region in the LiF-KCl-KBr stable triangle was outlined.  相似文献   

18.
R. Dean Astumian 《Tetrahedron》2008,64(36):8287-8291
Chemists have made great progress in synthesizing molecules that emulate in part the remarkable properties of biological molecular motors, most especially the ability to use chemical energy to drive directed motion and do mechanical work. Here the mechanism of a molecular motor is treated as a renewal process in which the motor molecule fluctuates away from, and then returns to some arbitrary initial configurational state. During this excursion, some number of fuel molecules will have been catalytically converted to product, and the motor will have undergone some number of mechanical cycles in which work is done on the environment. The dependences of the number of catalytic and mechanical processes per renewal obey reciprocal relations for arbitrarily strong load force and chemical driving force. These relations characterize the behavior of the system far from thermodynamic equilibrium in the same way that the Onsager reciprocal relations characterize the system close to thermodynamic equilibrium.  相似文献   

19.
倒数示波计时电位法   总被引:1,自引:0,他引:1  
毕树平  高鸿  都思丹  王忠 《化学学报》1992,50(11):1123-1128
使用dE/dt的倒数对E作图的示波计时电位法,称为倒数示波计时电位法.dE/dt-E曲线上的切口在dE/dt^-1-E上变成峰,可以方便地扣除充电电流,提高分析测试的灵敏度.  相似文献   

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