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141.
溶剂聚合膜pH电极作内电极的气敏电极的研究 总被引:1,自引:0,他引:1
研究了以中性载体为活性物的石墨内导平头溶剂聚合膜(SPM)pH电极作内电极的二氧化碳和氨气敏电极。电极的性能取决于中性载体的特性,其中以菸酸十八酯为内电极膜活性物的二氧化碳气敏电极和以二辛基十八胺为活性物的氨气敏电极性能较佳。二氧化碳气敏电极用作丙酮酸脱羧酶酶电极的原电极,其性能院于传统的以玻璃pH电极作内电极的二氧化碳气敏电极。 相似文献
142.
An enhanced etched electrochemical (EC) detection technique has been developed for CE in micron inner diameter capillaries. The design improvements allow for better alignment between the capillary bore and the electrode. This new method involves utilizing a carbon fiber microelectrode and etching both the carbon fiber and the detection end of a micrometer-sized inner diameter capillary to limit dead volume and analyte diffusion at the amperometric EC detector. To understand the factors affecting enhanced detector efficiency, a detailed examination of the relationship between detector design and performance has been completed by exploring the effects of varying electrode diameter, tip shape, and size, in addition to the etch length of the capillary outlet. The enhanced detection provides peak efficiencies as high as 75000 theoretical plates and estimated detection limits as low as 40 nM for dopamine. This etched detection method should further facilitate volume-limited sample analysis by CE. 相似文献
143.
Different copper/zirconium-yttrium catalysts have been tested in carbon black oxidation reaction. Supported mainly on differential thermal analysis and temperature programmed reduction, two different mechanisms have been proposed to explain the catalytic results. In the absence of copper, it has been shown that Zr3+ ions and associated anionic vacancies are responsible to the catalytic enhancement observed in the mixed oxides, oxygen species being activated on these sites. Among mixed zirconia-yttria solids, ZrO2-5 mol%Y2O3 is the most active catalyst. Copper impregnation on these oxides leads to the formation of different copper species. Small particles of CuO in low interaction with the support, induce a catalytic improvement due to the highest reducibility of these species. Moreover, in order to be more efficient, CuO species should have some interactions with the support, since impregnated samples are more active than the simple mechanical mixtures. 相似文献
144.
Dong Xie Xian-hong Wang Xiao-jiang Zhao Fo-song Wang 《高分子科学》2005,(6):671-674
Rare-earth ternary catalysts Y(CCl3COO)3-ZnR2-glycerin were prepared for the copolymerization of carbon dioxide and propylene oxide (PO), where dialkylzincs (ZnR2) were diethylzinc, di(n-propyl)zinc, di(n-butyl)zinc, di(i-propyl)zinc, di(i-butyl)zinc, di(s-butyl)zinc,respectively. The Y(CCl3COO)3-ZnR2-glycerin catalysts displayed the highest catalytic activity at the molar ratio of Y(CCl3COO)3:ZnR2:glycerin = 1:20:10. In the same copolymerization condition, catalysts containing dialkylzincs with branched alkyl group showed lower catalytic activity than that with primary alkyl group. For those catalysts including dialkylzincs with primary alkyl group, their catalytic activity decreases with increasing number of carbon atom in the alkyl group with the following sequence: Y(CCl3COO)3-ZnEt2-glycerin 〉 Y(CCl3COO)3-Zn(n- Pr)2-glycerin〉Y(CCl3COO)3-Zn(n-Bu)2-glycerin. However, the alkyl group in the dialkylzinc does not influence the insertion of PO into the propagation chain end. 相似文献
145.
146.
Time-of-flight mass spectrum of C_nB~- has been recorded on a selfbuilt instrument with laser vaporization of tetraphenylboron sodium. By analysis of the com-position of the anions, it is found that number of the boron atoms in any of these ions equals to the number of the charges carried by the anion, and the sum of the numbers of the carbon and boron atoms in these species are always the odd numbers. The experimental results show that boron atom has a strong tendency to attract an electron so that those C_nB~- will have similar electronic structures as C_n, and carbon clusters with odd members are always more stable than their even neighbors. 相似文献
147.
碳纤维汞膜微电极1.5次微分伏安法测定米托蒽醌的研究 总被引:4,自引:1,他引:4
米托蒽醌(MXT)能吸附在碳纤维汞膜微电极表面,阴极溶出时,产生一个灵敏的1.5次微分溶出峰,其峰电流和米托葱酿的浓度在1.0×10-5mol/L~1.3×10-9mol/L范围内具有良好的线性关系,经3min的富集,检出限可达1.0×10-10mol/L,据此建立了测定MXT的灵敏的新方法,本文讨论了实验条件,并对血样中的MXT进行了测定。 相似文献
148.
鞠 《高等学校化学学报》1992,(11)
研究了温度对碳纤维微电极上伏安曲线的影响及温度与电极电位的关系,测定了电极反应的热力学参数.由电流与温度的关系测定了去极剂的扩散活化能E_(al)和D_o,利用微电极具有高速传质的特性,测定了常规电极上为可逆反应的电极反应标准速率常数(?),并通过(?)与温度的关系测定了电极反应的活化能. 相似文献
149.
Kedong Xia Junpo Guo Cuijuan Xuan Ting Huang Zhiping Deng Lingxuan Chen Deli Wang 《中国化学快报》2019,30(1):192-196
Nitrogen doped carbon nanosheets supported molybdenum carbides nanoparticles (MoxC/NCS) have been synthesized by tuning the mass ratio of melamine and ammonia molybdate. The Mo2C/NCS-10 exhibits superior electrocatalytic performance and stability for HER, which was attributed to N-doped carbon nanosheets, small particle size, mesoporous structure, and large electrochemical active surface area. 相似文献
150.
《Electroanalysis》2006,18(11):1131-1134
The direct electrochemistry of glucose oxidase (GOD) was revealed at a carbon nanotube (CNT)‐modified glassy carbon electrode, where the enzyme was immobilized with a chitosan film containing gold nanoparticles. The immobilized GOD displays a pair of redox peaks in pH 7.4 phosphate buffer solutions (PBS) with the formal potential of about ?455 mV (vs. Ag/AgCl) and shows a surface‐controlled electrode process. Bioactivity remains good, along with effective catalysis of the reduction of oxygen. In the presence of dissolved oxygen, the reduction peak current decreased gradually with the addition of glucose, which could be used for reagentless detection of glucose with a linear range from 0.04 to 1.0 mM. The proposed glucose biosensor exhibited high sensitivity, good stability and reproducibility, and was also insensitive to common interferences such as ascorbic and uric acid. The excellent performance of the reagentless biosensor is attributed to the effective enhancement of electron transfer between enzyme and electrode surface by CNTs, and the biocompatible environment that the chitosan film containing gold nanoparticles provides for immobilized GOD. 相似文献