毛细管电色谱(CEC)手性分离技术的回顾、现状与未来 Ⅱ CEC手性固定相(CSPs)的研究进展

本文通过对毛细管电色谱手性分离文献的回顾,对其手性识别的基本理论、操作参数的影响和手性固定相(CSPs)的研究现状作比较全面的综述,并对该领域未来的发展方向作出展望,旨在引起国内色谱工作者对该领域研究的关注。     

超临界流体色谱分离手性药物研究进展

本文根据SFC所用流动相模式不同将手性固定相分为四大类,即正相模式、反相模式、极性有机模式和极性离子模式,并综述了各类模式下SFC分离手性药物的进展。SFC法作为一种很有潜力的色谱分离技术,将在手性药物分离及分析等方面发挥巨大作用。     

手性气相色谱法——环糊精衍生物为固定相

色谱手性分离是目前药物、生命科学与环境科学领域中的重要课题,是当前分离分析的热点。本书作者长期工作在国际著名手性色谱分离实验室与色谱柱生产企业,书中许多实例为作者在手性气相分离方面的工作和经验。全书共分7章。详细地介绍了利用气相色谱方法对手性化合物进行分离分析的全部技术,重点是手性分离色谱柱的制备、手性固定相的选择和未商品化的色谱固定相的利用。读者对象:药物、生命科学、环境科学等领域色谱分离与研究人员,大专院校相关专业师生。     

高效液相色谱进展（五）——HPLC手性固定相和色谱柱近年的发展

液相色谱手性固定相和色谱柱是HPLC的重要课题，近年受人们高度重视，因为在生物和药物领域有大量的手性化合物存在，需要识别和拆分它们，HPLC是一种首选的方法。本文综述了HPLC手性固定相和色谱柱最近几年的发展，着重讨论了应用较多的一些手性固定相和色谱柱。     

硒代缩水甘油醚在Chiralcel OJ-H手性柱上的拆分

采用高效液相色谱Chiralcel OJ-H色谱手性柱,在正相条件下对硒代缩水甘油醚手性化合物进行手性拆分,讨论流动相的组成、溶质的结构对手性拆分的影响。     

气相色谱手性毛细管柱的制备

合成了一种新的β－环糊精衍生物手性固定相。以甲基苯基聚硅氧烷作为手性固定相的稀释剂,采用超动态法成功地制备了高效弹性石英毛细管柱。考察了手性毛细管柱的色谱性能,成功地分离了一系列对映体。     

键合支链淀粉（3,5-二甲基苯基氨基甲酸酯）手性固定相的制备及手性拆分应用

采用双官能团键合法,以六亚甲基异氰酸酯为键合试剂,自制了键合支链淀粉（3,5-二甲基苯基氨基甲酸酯）手性固定相。在所制得的固定相上,以正相、反相、极性有机相多种色谱分离模式对8种含苯环的手性化合物进行了拆分。实验结果发现,正相模式下,在流动相正己烷或正己烷/异丙醇中添加二氯甲烷、三氯甲烷、四氢呋喃有利于手性化合物的拆分。在反相和极性有机相色谱条件下,此固定相仍具有手性拆分能力;除样品7外,其余手性样品均获得不同程度的手性分离。     

使用含白蛋白支持电解质的毛细管亲和区带电泳进行手性分离

毛细管亲和区带电泳已用于某些药物成分的手性分离研究。牛血清白蛋白（ＢＳＡ）也被用作手性选择剂加入到电解质中。对于新喹啉杀菌的手性分离，磷酸盐缓冲液比硼酸盐缓冲液更适合作支持电解质。本文考查了ＢＳＡ浓度、白蛋白种类、ｐＨ值、手术加和以及电压对分离的影响。结果表明，手性分离可在ｐＨ７￣８范围内进行。对映异构体的迁移和立体选择性可通过改变蛋白质浓试（大于０．２％ｗ／ｖ）、电压以及加入氨基酸作为手性修饰剂     

手性农药在纤维素—氯苯基氨基甲酸酯手性固定相上的拆分

分别以4,4′-二苯基甲基二异氰酸酯或六亚甲基二异氰酸酯为连接臂,采用6-位选择键合法,将纤维素-(3-氯苯基氨基甲酸酯)键合于氨丙基硅胶上,制备了两种键合型纤维素-(3-氯苯基氨基甲酸酯)手性固定相(BClCTPC-CSP1,BClCTPC-CSP2),同时制备了涂敷型纤维素(3-氯苯基氨基甲酸酯)手性固定相(CClCTPC-CSP)。在正相模式下,对4种手性农药进行了拆分。实验结果表明:所制备的手性固定相均具有一定的手性识别能力,键合型手性固定相可以使用四氢呋喃作流动相极性改性剂,使得在常规流动相中三种固定相上未获拆分的手性农药甲霜灵获得拆分。     

环糊精毛细管区带电泳法研究手性药物对映体分离

介绍了本科研组在手性添加剂种类、缓冲溶液pH值、有机添加剂对手性分离的影响,三种新型带电环糊精的手性拆分以及二元环糊精体系的协同效应等三个方面的工作。认为选择合适的手性选择剂的类型是最为重要的因素。展望在众多的对映体分离手段中,毛细管电泳大有后来者居上之势     

Investigation of biomass formation during the biodegradation of ester base lubricants

Comparative studies were performed to assess the biodegradation of the synthetic lubricant base stock, Priolube 3999, by P. putida using the CEC test method and manometric respirometry. Supplementary analyses demonstrated the production of a non-readily biodegradable metabolite, trimethylol-propane, the alcohol group of the candidate fluid. Evidence was obtained that indicated that a significant fraction of carbon added as test substance remained incorporated in the biomass. The implications of these results are discussed and modifications to the CEC test proposed.     

Tribological Behavior of Carbon Nanotube-Reinforced AZ91D Composites Processed by Cyclic Extrusion and Compression

Reciprocating wear tests were conducted to assess the wear resistance of CNT-reinforced AZ91D composites prepared by cyclic extrusion and compression (CEC). Effects of CEC, CNTs, and wear parameters on the tribological behavior of the composites were discussed. Results show that the matrix grain of the 0.5 wt% CNTs/AZ91D composites is largely refined from ~?112 µm to 126.6 nm after eight passes of CEC. Accordingly, the hardness of the composites is increased by more than 82.0%. The wear rate of the CNTs/AZ91D composites decreases with the implement of CEC and the addition of CNTs. The lubrication effect of CNTs diminishes after CEC. Besides the reinforcing effect, the incorporated CNTs help to liberate the friction heat of the CNTs/AZ91D composites and reduce the welding of the wear debris due to their extraordinary thermal conductivity.     

Separation with a Liquid Stationary Phase: The Countercurrent Chromatography Technique

Abstract

Countercurrent chromatography (CCC) does not necessarily involve two liquid phases flowing in opposite directions. CCC is a liquid chromatography technique with a liquid stationary phase and an immiscible liquid mobile phase. It is not a liquid-liquid extraction technique, but a chromatographic technique. It is shown that high performance liquid chromatography (HPLC) and CCC do not operate in the same range of capacity factors and partition coefficients. The efficiency is low in CCC compared to HPLC. However, this drawback is compensated by the phase ratio V_S/V_M (stationary phase volume over mobile phase volume) which can be higher than 1 in CCC and is lower than 0.05 in LC. The resolution factor, Rs, can be higher than 1.5 in CCC for solutes with partition coefficients around 1. The solutes access the volume of the liquid stationary phase, which explains the high possible loadability of CCC compared to HPLC. The two types of modern high speed CCC apparatuses, hydrostatic and hydrodynamic, are discussed. The commercially available instruments are briefly described.     

Metabolomic applications of HILIC–LC–MS

Hydrophilic interaction liquid chromatography (HILIC), although not a new technique, has enjoyed a recent renaissance with the introduction of robust and reproducible stationary phases. It is consequently finding application in metabolomics studies, which have traditionally relied on the stability of reversed phases (RPs), since the biofluids analyzed are predominantly aqueous and thus contain many polar analytes. HILIC's retention of those polar compounds and use of solvents readily compatible with mass spectrometry have seen its increasing adoption in studies of complex aqueous metabolomes. This review describes the stationary phases and their features, surveys HILIC–LC–MS's role in metabolomics experiments, discusses approaches to data extraction and analysis including multivariate analysis, and reviews the literature on HILIC–MS applications in metabolomics. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 29:671–684, 2010     

Assessment of the biodegradability of mineral oil and synthetic ester base stocks,using CO2 ultimate biodegradability tests and CEC-L-33-T-82

The EPA (Gledhill) Shake Flask test, OECD Modified Sturm test, and CEC (CEC-L-33-T-82) Biodegradability test have been used to assess the degradability of mineral oil, natural ester, and synthetic ester base stocks. The Shake and Sturm tests are ultimate biodegradability tests which determine the percentage of test material carbon converted to CO₂ over a 28-day period; the CEC test determines, at 21 days, the disappearance of the carbon-hydrogen stretch in Freon extracts of the test medium. In all three tests, the test material is added to a mineral salts medium, the medium is inoculated with mixed liquor from a municipal waste water treatment plant and test flasks are shaken. The Shake Flask and CEC tests were able to show expected differences in degradability between paraffinic and naphthenic mineral oils. A poor correlation was found between ultimate biodegradability test results and results from the CEC test when synthetic esters were studied. Dissolved organic carbon (DOC) analysis of the test medium indicated that degradation of some synthetic esters led to the accumulation of water-soluble metabolites which are not extractable into Freon, as required for quantification by the CEC test. Thus, while the CO₂ tests detected differences in the degradability of these test materials, the CEC test did not. The CEC test can, therefore, overestimate degradability of some synthetic esters, leading to the erroneous conclusion that these materials would meet OECD Ready Biodegradability criteria. Biodegradability results for the EPA, OECD, and CEC tests are presented and results compared.     

Investigation of tribological behaviors of annular rings with spiral groove

A series of experiments is conducted to study the tribological behavior of spiral groove thrust bearings. The experimental system consists of a nominally flat upper ring mating with a stationary spiral groove lower ring in fully flooded lubrication environment. Spiral groove thrust bearings with different spiral angles subjected to different loads and speeds are tested. Stribeck-like curves are obtained and their characteristics are discussed. Transition points from mixed to hydrodynamic lubrication are experimentally established. In addition, a theoretical model is developed to gain further insight into the frictional characteristics of spiral grooves in both the hydrodynamic regime and the mixed lubrication regime.     

二进小波变换在建筑结构振动中的应用

探讨了二进小波变换在建筑结构振动中的应用。提出了一种检测结构受到冲击的新小波方法,利用该方法有效地完成了结构振动特征信号的提取,首先分析了二进小波的定义、特性及检测突变的原理,之后以一典型信号作检测原理的数值模拟,最后通过一框架模型实验对该法进行了验证,研究表明,二进小波变换方法在建筑物受冲击或振动等非平称信号作用时,具有较好的分析效果和实用价值。     

Investigation of tribological behaviors of annular rings with spiral groove

A series of experiments is conducted to study the tribological behavior of spiral groove thrust bearings. The experimental system consists of a nominally flat upper ring mating with a stationary spiral groove lower ring in fully flooded lubrication environment. Spiral groove thrust bearings with different spiral angles subjected to different loads and speeds are tested. Stribeck-like curves are obtained and their characteristics are discussed. Transition points from mixed to hydrodynamic lubrication are experimentally established. In addition, a theoretical model is developed to gain further insight into the frictional characteristics of spiral grooves in both the hydrodynamic regime and the mixed lubrication regime.     

发射药老化样品中氧化亚氮气相色谱测定方法

研究了用气相色谱电子捕获检测器（GC-ECD）和气相色谱热导池检测器（GC-TCD）测定发射药老化后N2O含量的方法。考察了电子捕获检测器和热导池检测器对N2O含量的不同测量范围和不同固定相以及不同色谱条件对测定的影响。采用GDX-104为固定相的色谱柱和热导池检测器,对不同批次发射药老化后样品中的N2O含量进行了测定。结果表明,N2O的色谱保留时间在1.6min左右,4批老化后发射药样品中的N2O含量分别为376.8、264.7、1036和1812μL/L,RSD分别为4.11%、2.64%、3.87%和0.78%。