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151.
C18固相萃取膜适宜处理大体积地下水样现场采样而且易于运输、贮存。利用C18固相膜萃取以及GC/MS联用的方法对地下水中痕量半挥发性有机污染物进行了萃取以及定性、定量分析。优化了固相膜萃取的地下水采样量和浓缩体积。有机氯农药和多环芳烃的平均回收率分别为85%~110.1%、90.3%~115.1%;方法检出限达到10^-9g/L;相对标准偏差均小于15%。本方法用于北京地区地下水中的有机污染物分析,并给出地下水样C18固相膜萃取的GC/MS测定结果。 相似文献
152.
杂多酸在活性炭上的固载化Ⅲ.活性炭在酸性介质中对钨硅杂多酸(SiW_(12))的吸附 总被引:1,自引:0,他引:1
在氢离子浓度均为3mol/L的硫酸,盐酸,磷酸,醋酸水溶液中和冰醋酸中研究了具有Keggin结构的硅钨杂多酸(SiW_(12))在不同来源活性炭上的吸附作用。各活性炭对SiW_(12)吸附等温线的形式是不相同的,吸附剂载体的微孔结构以及杂多酸的溶剂化起着重要的作用。并且在无机酸介质中,杂多酸的吸附量比在水溶液中成规律性地增加,且与酸强度成正比关系。在有机酸介质中,吸附作用比较复杂。根据所得结果,提出了在酸性介质中杂多酸在活性炭表面的吸附模型。 相似文献
153.
154.
A molecular level understanding of the photoreactivity of self-assembled monolayers (SAMs) becomes increasingly important as the spatial resolution starts to be limited by the size of the resist and the spatial extent of the photochemical reactions in photoresist micropatterning. To this end, a number of surface characterization techniques were combined to understand the reactive agents, reactive sites, kinetics, and reaction pathways in the UV photoreactivity of octadecylsiloxane (ODS) SAMs. Quantitative analysis of our results provides evidence that ground state atomic oxygen is the primary reactive agent for the UV degradation of ODS SAMs. UV degradation, which follows zero-order kinetics, results in the scission of alkyl chains instead of the siloxane headgroups. Our results suggest that the top of the ODS SAMs is the preferential reactive site. Using a novel, highly surface sensitive technique, fluorescence labeling of surface species, we identified the presence of submonolayer quantities chemical functional groups formed by the UV degradation. These groups are intermediates in a proposed mechanism based on hydrogen abstraction. 相似文献
155.
原子发射光谱法间接测定黄连素片剂中盐酸小檗碱的研究 总被引:1,自引:0,他引:1
本文提出了离子对-原子发射光谱间接测定黄连素片剂中盐酸小檗碱的新方法。发现用1,2-二氯乙烷作萃取剂效果最佳。用此怯测定实际样品的结果与药典法一致,相对误差为0.61%,单一测定的相对标准偏差为0.67%。本法还可在盐酸普鲁卡因共存下单独测定盐酸小檗碱。方法可靠、适用,选择性较好。 相似文献
156.
Ye S Zhou W Abe M Nishida T Cui L Uosaki K Osawa M Sasaki Y 《Journal of the American Chemical Society》2004,126(24):7434-7435
A highly selective ligand exchange reaction is realized in the self-assembled monolayer (SAM) of a triruthenium cluster on a gold electrode surface under precise electrochemical potential control. CO as well as NO molecules, which are known to play key roles in many chemical, biological, and environmental systems, can be efficiently introduced into the SAM by electrochemically tuning the electronic state of the Ru site. These unique surface reactions are more convenient and efficient than conventional ligand exchange reactions in solution and could be used for the elucidation of the electron-transfer mechanism in a biological system as well as in the development of molecular sensors and devices. 相似文献
157.
Yuming Dong Yuqiang Ding Weifu Dong Cheng Yang Xuefeng Liu Ye Fan Jing Wang Qingwei Pan 《大学化学》1986,35(10):71-76
Based on the development prospect of cosmetics industry, the advantage of light industry characteristic and the foundation of applied chemistry in Jiangnan University, a systematic upgrading of applied chemistry was carried out through "emerging engineering education (3E)" project "upgrade and practice of chemistry-related majors of local and/or trade university responding to the social developments" supported by the Ministry of Education. On the basis of investigation and analysis, the orientation and training goal of applied chemistry were updated first, and then the curriculum system was determined and the curriculum construction is strengthened, so as to achieve more distinctive characteristics, more solid foundation and more comprehensive quality. In view of the new requirements of the 3E for talent training, some practices have been formed in the aspects of multi-disciplinary integration, multi-angle coordination and close integration to industry. Contributing the development of cosmetics industry and seizing the commanding point of science and technology from the perspective of talent training, will play a unique role in human social progress. 相似文献
158.
M. G. Fan Y. C. Liang Y. F. Ming J. X. Chen T. Ye Q. Y. Zhang B. A. Xu S. Jin 《Research on Chemical Intermediates》1998,24(9):961-971
Photophysical behavior of spiro[1,3,3-trimethylindolino-2,3′-naphtho[2,1-b]-1,4-oxazine] (SP1) and spiro[1,3,3,2′-tetramethylindolino-2,3′-naphtho[2,1-b]-1,4-oxazine] (SP2) were studied. The fluorescent species and their spectra of SP1 and SP2 in polar solvents (acetonitrile and methanol) and non-polar solvent (cyclohexane) were investigated. The fluorescence decay
in polar solvents was studied by picosecond time-correlated single photon counting. In most cases, fluorescence decay obeyed
triexponential decay kinetics. The major fluorescent species is an excited intermediate which has similar conformation as
its precursor (1
SP
*) formed after the bond cleavage between spirocarbon and oxygen in oxazine ring. The effects of molecular structure and solvent
polarity on fluorescence spectra and fluorescence decay lifetime were studied. 相似文献
159.
Xiao Ying Xu Feng Cheng Jian Hua Shen Xiao Min Luo Li Li Chen Li Duo Yue Yi Du Fei Ye Shan Hao Jiang Da Yuan Zhu Hua Liang Jiang Kai Xian Chen 《International journal of quantum chemistry》2003,93(6):405-410
Docking simulation of 18 agonists with the ligand binding pocket (LBP) of PPARγ has been performed. The binding conformations and binding affinities of these agonists were obtained by use of the flexible docking protocol FlexX. Test compound calculations indicated that FlexX can reproduce the binding conformation of the crystal structure (root mean square deviation = 1.43 Å); moreover, the predicted binding affinities correlate well with the activities of these agonists. The interaction model and pharmacophore of PPARγ agonists were derived and the difference in biologic activities of these agonists can be well explained. The PPARγ agonists must have both polar head and the hydrophobic tail, which form hydrogen bonds and hydrophobic contacts with hydrophilic and hydrophobic regions of the LBP of PPARγ, respectively. In addition, a suitable linker is also necessary. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 93: 405–410, 2003 相似文献
160.