毛细管气相色谱法研究硝基氨基甲苯异构体在SE-30、SE-54中的热力学性质

通过对色谱分离过程的热力学处理,得到了用毛细管色谱法测定溶质在溶剂中的溶解热力学性质的关系式,利用该式测定了硝基氨基甲苯的五种异构体在SE-30,SE-54固定液中的溶解焓和溶解熵,并对结果进行了定性解释。     

交链SE-54弹性石英开管柱

近年来国内外色谱工作者为了寻求高效、内壁惰性及热稳定性好的毛细管柱进行了许多研究,交链弹性石英开管柱就是其中的一个新进展。国外已有定型交链开管柱供应,如美国、意大利及日本有出售15～25米长的内径0.20～0.30毫米的交链SE-30、SE-52、SE-54、OV-101及OV-1毛细管柱,但在国内此类柱子还处于研制阶段。本文介绍我们最近试制的内壁交链SE-54弹性石英开管柱,并对其性能进行了评价。交链毛细管柱制备方法原理是将橡胶工业中引发聚合物分子使之生成交链高分子的技术     

单壁碳纳米管+SE-30毛细管柱的制备研究及对多种物质的拆分

使用单壁碳纳米管(SWNTs)作气相色谱的固定相, 并用静态涂渍法在单壁碳纳米管内壁涂渍浓度不同的SE-30固定液. 为考察固定液浓度不同的几根毛细管柱的柱性能, 对多种物质进行了拆分, 并将该拆分结构与直接涂渍SE-30柱的毛细管柱性能进行对照. 实验结果表明: 键合了SWNTS再涂渍SE-30的毛细管柱较之直接涂渍SE-30的毛细管柱拆分效果有所改进, 但存在一定的拖尾现象. 此外, 前者对气体有较好的拆分效果, 且其效果随SE-30浓度按一定规律变化. 从分离性能来看, 键合了SWNTS再涂渍SE-30的固定相对气体的分离具有较好的效果.     

交联SE-54弹性玻璃毛细管柱研究

弹性玻璃毛细管柱的出现为毛细管色谱技术提供了一种新型柱。最近我们应用硅膜改性法成功地惰化了弹性玻璃毛细管柱而不损害其强度,使这种柱型有了良好的发展基础。关于交联弹性石英柱的制备巳有不少研究,但在硅膜改性玻璃毛细管柱上进行交联的工作尚未见报道。本文介绍SE-54弹性玻璃毛细管交联柱的制备和性能研究。在拉制好的     

基于溶解热力学原理对纳米卤化银热力学性质的研究

在室温下,可控制备了系列纳米卤化银(Ag X)材料,并对其组成、形貌及结构进行了表征.基于块体卤化银与纳米卤化银热力学性质的本质差异,结合溶解热力学Debye-Hückel等基本理论公式,通过与块体材料对比,导出了纳米卤化银的表面热力学、偏摩尔表面热力学和规定热力学函数的关系式.为测定难溶盐类纳米材料的表面热力学和规定热力学函数提供了行之有效的新方法.     

278.15至318.15K下二氧化碳在氯化钠葡萄糖水溶液中的溶解度和活度系数

用自行研制的二氧化碳溶解度测量仪在不同温度下测定了二氧化碳在不同氯化钠浓度15%葡萄糖水溶液中的溶解度和活度系数,确定了Henry常数和盐析常数,Henry常数与温度关系的经验方程为lgS=A/T+B+CT,并计算了二氧化碳溶解过程的各个热力学量。     

毛细管柱气相色谱法测定银杏叶中可溶性单糖

采用恒温水浸泡提取可溶性单糖,所得浸出液经减压蒸发(60℃)干燥后用二甲基亚砜(DMSO)作溶剂使残渣溶解,六甲基二硅烷(HMDS)和三甲基氯硅烷(TMCS)作硅烷化试剂,将单糖衍生化为三甲基硅烷衍生物,以肌醇为内标物,用SE-30毛细管色谱柱,气相色谱法测定了银杏叶中7种单糖含量,测定标准偏差小于10%.同时测定了春秋两季所采摘的样品以及从叶柄的所采样品中的单糖含量.试验结果表明:春季银杏叶中各单糖含量均高于秋季黄叶,春季银杏叶叶柄中除果糖外均高于叶中各单糖含量.     

二氰胺1-羟乙基-3-甲基咪唑离子液体的合成及对糖类化合物的溶解性能

根据离子液体结构-性能的关系,设计合成了一种新的低熔点、低黏度的功能化离子液体二氰胺1-羟乙基-3-甲基咪唑[Hemim][N(CN)2],并在298.2～353.2K的温度范围内测定了α-D-木糖、α-D-葡萄糖、D-果糖、蔗糖、D-乳糖、麦芽糖、棉子糖和木聚糖在该离子液体中的溶解度,计算了糖类化合物在离子液体中的标准溶解热力学参数.实验结果表明,除木聚糖外其他糖类化合物在[Hemim][N(CN)2]中均具有较高的溶解度,且其溶解度随着温度的升高显著增大.木聚糖属于多聚糖,溶解度较小,但温度效应非常明显.糖类化合物的溶解热力学参数SΔGo、TΔSSo和ΔHSo均为正值,且ΔHSoTΔSSo,说明溶解为焓控制过程.红外光谱结果表明,在溶解过程中木聚糖的氢键受到了一定程度的破坏,但它的结构并未发生明显的变化.     

Ag3PO4溶解热力学函数的晶面效应与温度效应

在室温下制备了立方体{100}、 四面体{111}、 菱形十二面体{110}和块体Ag₃PO₄微晶, 并进行了表征. 测定了其在不同温度下水溶液中的电导率, 结合强电解质溶液和溶解热力学理论, 得到了Ag₃PO₄微晶的溶解热力学函数. 以具有不同晶面的Ag₃PO₄微晶为模型, 研究了纳米材料溶解热力学函数的晶面效应和温度效应. 结果表明, 具有{110}晶面的菱形十二面体Ag₃PO₄的标准摩尔溶解吉布斯自由能()、 标准摩尔溶解焓()和标准摩尔溶解熵()最大, 具有{100}晶面的立方体Ag₃PO₄次之, 具有{111}晶面的四面体Ag₃PO₄最小; 溶解平衡常数(K_{\mathrm{SP}})和随着温度的升高而增大.     

气体的溶解度与温度的关系

用热力学原理导出气体在液体中的溶解度与温度之间的关系.当溶解过程减熵时,溶解度随着温度的升高而减小;当溶解过程增熵时,溶解度随着温度的升高而增大.     

Partition of supercritical n-pentane into SE-54 and SE-30 stationary phases in capillary supercritical fluid chromatography

Summary The mass spectrometric tracer pulse (MSTP) chromatography method was used to measure the amount of supercritical n-pentane dissolved or adsorbed into SE-54 and SE-30 capillary columns. Partition data were measured above the critical point of n-pentane at temperatures from 200 ° to 300 °C and pressures between 35.04 and 54.42 atm. The data obtained provide evidence for mobile fluid solubility or adsorption into the stationary phase under the conditions of supercritical fluid chromatography (SFC). At 220 °C, solubility and/or adsorption of supercritical n-pentane decreases by increasing the pressure and reaches a minimum at approximately 45.00 atm. The effect of mobile-fluid pressure on its solubility or adsorption becomes limited at temperatures over 260 °C. This study demonstrates the unique experimental capabilities of the MSTPC method for quantitative measurement of the physico-chemical interaction of the complex multicomponent system encountered in SFC which is not possible by any other technique. An innovative instrumental design for modification of GC/MS systems for SFC, GC/MS operation is also described.

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Verteilung von superkritischem n-Pentan in den stationären Phasen SE-54 und SE-30 bei der Capillar-Chromatographie mit superkritischen fluiden Phasen

     

C_5馏分及其羰化产物的毛细管气相色谱分析

石油裂解副产物C5馏分及其羰化产物是成分较为复杂的混合物,尤其是C5馏分中1,3-环戊二烯和顺-1,3-戊二烯的物性更为接近。用SE－54弹性石英毛细管柱和角鲨烷玻璃毛细管柱分别对C5馏分及其羰化产物进行了分析,使各组分达到了很好的分离。     

Preparation and Characterization of Sol-Gel SE-30-Coated Silica Stationary Phase for Capillary Liquid Chromatography

A sol-gel chemistry-based polymer coating approach was developed for the preparation of a novel polysiloxane-coated silica stationary phase for capillary liquid chromatography. SE-30, a commercial polysiloxane stationary phase used in gas chromatography, was incorporated into the properly designed sol solution. Then the sol-gel mixture was introduced into a silica gel-packed capillary column by pressure. A thin film of sol-gel SE-30-coating is chemically bonded to the surface of silica gel particles by hydrolytic polycondensation under mild conditions without any free radical cross-linking procedures, therefore the sol-gel approach offers a simple and effective pathway to create a hybrid polymer-coated silica stationary phase. Various factors affecting column making were optimized and discussed in this report. The resulting stationary phase showed good permeability, mechanical robustness, high durability to alkaline mobile phase and satisfactory chromatographic performance in separations of polar and non-polar aromatic compounds. Linear solvation energy relationships (LSERs) studies indicate that the stationary phase has a reversed-phased character with SE-30 providing chromatographic functionality. The solute size and the solute hydrogen bond ability are major factors that principally govern the retention of test solutes.     

Gas chromatographic – mass spectrometric analysis of compounds generated upon thermal degradation of some stationary phases in gas chromatography – Part II

The applicability of capillary columns for gas chromatography is often limited by stationary phase degradation at elevated temperatures. In order to achieve a better understanding of column thermostability, column bleed products have been analyzed qualitatively by gas chromatography-mass spectrometry (GC-MS). Three silicone stationary phases were studied: SE-52, SE-54, and OV-1701. Each of these was immobilized in the columns. The proportion of cyclics containing diphenyl in column bleed from SE-52 reflected to a large extent the composition of the polymer, while for SE-54 the proportion of such cyclics was unexpectedly high. The polar moiety of OV-1701, the cyanopropyl(phenyl)siloxy unit, was found to exert a highly destabilizing effect on the polymer, and the thermal degradation products consisted mainly of cyclosiloxanes containing this unit.     

Simultaneous gas chromatographic determination of aliphatic C2−C20 n-carboxylic acids and their methyl esters using SE-30 and OV-351 quartz capillary columns

Summary Simultaneous determination of aliphatic C₂–C₂₀ carboxylic acids and their methyl esters was carried out using SE-30 and OV-351 quartz capillary columns with temperature programming. Complete resolution of all 36 components was achieved. On SE-30 the methyl ester and the corresponding free acid are eluted in turn, whereas on OV-351 acetic acid eluted after methyl octanoate, after which the C_n methyl ester and C_n-6 carboxylic acid (n>9) are eluted one after the other. A non-polar SE-30 column is better for long-chain acids giving sharp peaks without tailing, the analysis time of the mixture being less than 16 minutes. The weight response correction factors for compounds under optimum operating conditions are given.     

尸体脏器中敌百虫及其主要代谢物DDVP和水合氯醛的毛细柱GC/MS测定

本文应用Finnigan Mat 1020 GC/MS仪,以SE-54熔融硅毛细柱作分离柱,建立了尸体脏器中敌百虫及其主要代谢物DDVP和水合氯醛的分析方法。样品用CH_2Cl_2提取。敌百虫和DDVP的检测限均是15 ng,方法已成功用于刑事案件鉴定。     

Stimultaneous quantitative analysis using dual capillary columns of different polarities

Complex organic mixtures, such as coal liquefaction and oil shale products and by-products, are comprised of hundreds or thousands of individual components. State-of-the-art high resolution gas chromatography does not always provide sufficient resolution to allow accurate quantitation or identification of many compounds of interest. The concept of dual capillary column chromatography combines the different resolving characteristics of two capillary columns coated with different stationary phases into a single chromatographic run. In this approach, both columns are connected to the same injection port. Analysis of complex mixtures in this fashion can confirm the identification and quantitation of components on two columns of different polarity with little increased analysis time, can provide a means of obtaining quantitative data for individual components which are known to coelute on any one column, and can alert one to unknown coelution problems that would be undetected by gas chromatographic analysis on a single capillary column. Simultaneous dual column analysis was applied to three samples, the neutral polycyclic aromatic hydrocarbon (PAH) fraction of a Solvent Refined Coal-II (SRC-II) heavy distillate, the nitrogen-containing polycyclic aromatic compound (N-PAC) fraction of an SRC-II heavy distillate, and the basic fraction from a shale oil process water. Fused silica capillary columns coated with SE-54 and Durawax 3 were used for the analyses of the heavy distillate, while SE-54 an Carbowax 20M capillary columns were used for the analysis of the process water.