共查询到20条相似文献,搜索用时 62 毫秒
1.
《色谱》2016,(2)
光学吸收检测器是液相色谱仪最常用的检测器之一,检测池是此种检测器的核心部分,是获得光穿过样品信息的重要部件,其设计影响检测器的性能。为了提高检测器的信噪比,减小检测池引起的色谱峰展宽,需要设计更长光程、更小体积的检测池,同时还要保证一定的光通量。受加工技术的限制,增大光程、减小池体积和保证光通量通常很难兼顾,这对优化检测池的设计和加工、提高检测器性能提出了挑战。本文以光学吸收检测器的检测原理为基础,从增大光程、减小体积、利用全反射等角度综述了检测池设计的研究进展,同时对部分检测池的设计进行了详细说明。这些不同的设计思路和结构对于检测池的设计以及光学吸收检测器的研发具有指导意义。 相似文献
2.
3.
毛细管电泳高频电导检测器的研制 总被引:42,自引:0,他引:42
设计了一种新的毛细管电泳检测器.根据高频电导滴定原理,将电导电极做成两个金属圆筒套于分离毛细管外,并向两个电极施加高频电压.经毛细管分离后的组分流过两个电极之间时,高频电流发生变化,得到毛细管电泳图.该检测器具有应用范围广、操作简便及重现性好等优点,已初步应用于混合无机离子的测定. 相似文献
4.
摘要开发出一种新型电化学检测器,该检测器具有噪声低、基线漂移小、检测限低、整体体积小及便于现场使用等优点.在集成ITO电极的PDMS/玻璃毛细管电泳芯片上,利用多巴胺标准样品对该检测器的性能进行了评价. 相似文献
5.
本文设计了一个以多孔碳毡为工作电极的库化检测器并将其于用流动注射分析,以抗坏血酸、氢醌,没食子酸及二氧化硫为电活性物质检验该检测器的电化学特性。详细地研究了该检测器的库仑转换效率,选择性,线性范围,检测限及质量转移系数,并将该检测器作为双检测器流动注射分析系统中的“清除”电解池,用于酒中二氧化硫的测定,其结果与常规的吹气-氧化法非常吻合。 相似文献
6.
高效液相色谱电生Mn(Ⅲ)化学发光法检测人体血清和尿样中的卡托普利 总被引:1,自引:0,他引:1
设计了一个HPLC在线电生Mn(Ⅲ)化学发光检测器, 实现在线电化学反应, 从而产生反应活性很高的初生态氧化剂Mn(Ⅲ), 并与色谱柱后CP混合产生化学发光. 同时还能够根据需要调节电极反应和发光反应两者的介质, 满足柱后发光反应的最佳环境. 在优化流动相和化学发光检测条件的基础上, 将该检测器应用于人体血清和尿液中CP的测定. 相似文献
7.
8.
本文结合我们实验室所开展的一些工作,对多工作电极流动薄层电化学检测器及其电解色谱的一些新进展作了评述。着重介绍了三种结构类型即串联型、并联型和对向并列型的双工作电极检测器的设计和用途。本文还就双工作电极薄层电化学检测器与液相色谱结合的基本原理、优点和一些应用进行了讨论。最后简要地介绍了电解色谱的基本原理、进展及应用近况。 相似文献
9.
为了提高气相色谱仪用热导检测器的性能,设计了热导检测器的精密恒流源和差压检测电路。恒流源由场效应管IRF460、运算放大器AD8672和线性光耦HCNR201构成,低噪声电桥差压检测电路由2片AD8597构成。建立了差压检测电路的噪声模型,计算了噪声理论值。实际测试结果表明,该热导检测器的基线噪声达到4 μV, 50 min的基线漂移为15 μV,恒流源波动接近1 μA,优于现有热导检测器的技术指标。所介绍的设计方案和噪声分析方法对热导检测器的电路设计有较大的参考价值。 相似文献
10.
11.
用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%. 相似文献
12.
Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments. 相似文献
13.
Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives. 相似文献
14.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion. 相似文献
15.
The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula. 相似文献
16.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields. 相似文献
17.
Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines. 相似文献
18.
N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
The review contains a concise historical account and information on the most significant researches undertaken by the staff
at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry
of Heterocyclic Compounds.
Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008. 相似文献
19.
N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%). 相似文献
20.
Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones. 相似文献