便携式电动流动分析系统同时富集测定矿泉水中铬(Ⅵ)和镉(Ⅱ)

研究了电渗泵性能的改进以及双向电堆积系统各种参数对富集倍数的影响。提出一种电渗驱动与双向电堆积相结合的便携式电动流动分析系统,并采用石墨炉原子吸收法对矿泉水中铬(Ⅵ)和镉(Ⅱ)进行了同时富集和测定。检出限为9ng/L Cr(Ⅵ)和10ng/L Cd(Ⅱ)(n=11,3倍空白标准偏差)。加入相当于样品含量的Cr(Ⅵ)和Cd(Ⅱ),回收率分别为(105～107)±2％和(104～106)±2％(n=3)。     

电动流动分析的色谱分离研究

建立了一种基于增压电渗泵驱动、整体柱分离和紫外检测相结合的电动流动分析系统。研究了载流溶液中甲醇的体积分数对电渗泵空载流量、输出压强、移动相流量和分离度的影响。在4950V的外加电压下,以含0.5mmol/L六亚甲基四胺的45%甲醇溶液为泵载流,电渗泵的流量和输出压强分别为0.58mL/min和0.79MPa,以泵载流为流动相,该系统对苯和萘进行了反相色谱分离。电动流动分析系统设备简单、操作方便、功能多样。对苯和萘的分离结果表明,电动流动分析系统可用于样品的色谱分离。     

电渗泵在顺序注射萃取法测定酚中的应用

电渗泵是一种液流驱动泵，具有装置简单、载流无脉动、流量范围大和驱动电压适中等优点。用含1mmol/L三乙醇胺和0.1mmol/L四丁基溴化铵的乙醇溶液作泵载流，采用顺序注射萃取-分光光度法，对水样挥发酚进行了测定。有机载流可避免产生界面，减小检测干扰。载流添加剂可提高泵流量，改善流量稳定性。另外，还研究了酚的各种萃取条件。水中酚的检出限为7цg/L(3a，n=11)；回收率为92%-94%。方法证明了电动流动分析系统可用于溶剂萃取和有机分析。     

样品堆积——毛细管电泳的柱上浓缩技术

评叙了样品堆积，一种毛细管电泳提高检测灵敏度的柱上浓缩技术。样品堆积包括电堆积富集与场增加进样两种方法，分别在流动动力进样与电动进样过程中实现。本文从理论上说明了实现样品堆积及优化样品堆积富集效率须采取的实验措施，并对样品堆积目前的应用状况进行了全面介绍。     

新型毛细管等电聚焦驱动方法的建立及其应用

毛细管等电聚焦(CIEF)在生物分离分析领域中的发展迅速．CIEF可分为两步法聚焦和一步法聚焦．电渗流(EOF)可作为一种新的驱动力．Rassi等根据串连体系中电渗流速率将被平均化的原理,将未涂层毛细管与聚乙二醇涂层的毛细管通过聚四氟乙烯管耦合起来,成功地利用毛细管区带电泳快速分离蛋白．此外,利用电渗流输液原理设计的电渗泵还可用作流动注射和微柱液相色谱的驱动系统。     

毛细管等电聚焦和电渗泵驱动聚焦区带分离蛋白质

建立了一种利用电渗泵驱动毛细管内的聚焦区带,实现毛细管电泳等电聚焦分离蛋白质的方法。通过控制电压来调节泵的输出流量,从而调节聚焦区带的迁移速度。适用于毛细管电泳等电聚焦两步法分离蛋白质等两性物质。考察了对牛血清白蛋白和溶菌酶两种粗提蛋白质混合物的分离,迁移时间的RSD分别为1.6%和1.3%,峰面积的RSD均为1.6%,证明方法可行。     

双向电堆积与毛细管电泳联用对茶叶中咖啡酸及没食子酸的测定

采用在线双向电堆积与毛细管电泳联用技术测定茶叶中的有机酸离子。用砂芯取代盐桥隔离缓冲液与电极液,制成集成的双向电堆积装置,并用计算机程序控制分析过程。考察了电堆积时间、电堆积电压和样液体积等因素对富集倍数的影响。在优化的条件下,咖啡酸和没食子酸的富集倍数分别为24和20,检出限分别为0.4、0.2 mg/L。咖啡酸和没食子酸的线性范围分别为1.2~800 mg/L和0.8~800 mg/L。方法已应用于茶样中两种酸的测定,回收率为99%~109%。     

电渗泵中电渗流的控制

电渗泵是利用载流的电渗驱动原理，结合电色谱(EC)、毛细管电泳(CE)、液相色谱柱技术制作的输液微泵，是新颖的流体和样品输送技术。电渗泵中电渗流(EOF)控制方法与EC和CE等文献中的电渗流控制方法是相同的。本文对EC和CE等文献中有关EOF控制方法作了总结，并对电渗泵的研究现状和应用作一些前瞻分析。     

毛细管电泳样品电堆积富集过程影响因素的数值分析

毛细管电泳样品电堆积富集是一种通过缓冲溶液浓度的差异在毛细管中形成电场强度梯度,从而对样品进行浓缩的富集技术。本文在已有数学模型的基础上,对影响毛细管电堆积富集过程的因素进行了分析。计算结果发现,样品粒子表面所带的电荷电性以及带电量会影响粒子的电泳速度,进而影响富集过程;外加电势的大小会影响样品粒子到达检测窗口的迁移时间;而样品塞的初始长度则会影响样品所能达到的最大富集浓度以及达到最佳的富集效果所需要的时间。所得到的结果对样品电堆积富集技术的进一步完善具有一定的理论指导意义。     

毛细管电泳样品电堆积富集过程的数值研究

毛细管电泳样品电堆积富集过程可以浓缩样品组分,从而提高检测灵敏度,是一种有效的样品富集技术。本文通过合理的简化和假设,把毛细管中电堆积富集过程中所涉及的主要变量根据电势分布方程、缓冲溶液的浓度方程和样品粒子的质量传输方程进行耦合求解,建立了一个一维的数学模型,并应用有限元的方法对该模型进行了求解。计算结果给出了毛细管中缓冲溶液浓度及电场强度的分布随时间变化的过程,以及富集过程中毛细管中的电势分布曲线;得到了样品粒子浓度在电堆积富集过程和富集之后的再次扩散过程中的分布曲线以及正、负样品粒子的分离过程;最后分析了不同缓冲溶液浓度比对样品富集效果的影响。该研究为样品电堆积富集技术的进一步完善提供了一种简单可行的理论研究方法。     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

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.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

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%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

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.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.