高分子冠醚毛细管柱的性能研究

本文报道了3种新的聚硅氧烷侧链冠醚作气相色谱固定液,并涂渍成弹性石英毛细管柱,这种毛细管柱具有优良的色谱性能,它们具有柱效高,热稳定性好,选择性强的特点,适于分离各种异构体。     

Synthesis and characterization of novel polar-embedded silica stationary phases for use in reversed-phase high-performance liquid chromatography

We have developed a series of new C₁₀ dipeptide stationary phases via a simple and effective synthetic method. The preparation of the new phases involves the synthesis of silanes and the surface modification of silica. Chromatographic evaluations of these columns were performed using the Engelhardt, Tanaka, and Neue test mixtures. The applicability of these new stationary phases was also evaluated using a series of diagnostic probes including acids, bases or neutral compounds and several generic applications. These new C₁₀ dipeptide stationary phases showed excellent hydrolytic stability over a wide pH range. Like other existing amide-embedded columns, these new stationary phases exhibit higher retention for polar and hydrophilic compounds and different selectivity as compared to conventional C₁₈ columns. These new phases are compatible with 100% aqueous mobile phases, and also provide high column efficiency and good peak shapes for both acidic and basic compounds.     

The preparation of immobilized polysiloxane coated on packings materials for high-pressure gas chromatography

Summary In high pressure gas chromatography efficient columns can be packed by the slurry packing technique. However, polysiloxane stationary phases like OV 101 and OV 3 dissolve in the packing liquids. In order to make them suitable for slurry packing these stationary phases have to be made insoluble. This immobilization is achieved by bonding the stationary phases to the surface by means of a high temperature treatment. Successive layers are applied by recoating and are immobilized by a cross-link reaction. A range of loading percentages from 4 upto 20 by weight could be prepared in this way. On the evaluated columns compounds like butanol and dioxane elute as rather symmetrical peaks with the correct values for the retention index, indicating the absence of adsorption effects. Efficiency is good and bleeding rate is low. The columns could be successfully used in the analysis of turpentines.     

海藻糖、龙胆二糖、蜜二糖键合硅胶手性固定相的制备和性能

合成了海藻糖、龙胆二糖、蜜二糖三种二糖类键合硅胶高效液相色谱手性固定相,采用湿法装柱制备了色谱柱．在高效液相色谱正相条件下,该类固定相对醇类、胺类、氨基酸类对映异构体以及一些手性药物表现出了一定的拆分效果．特别是海藻糖固定相在所拆分的9种手性化合物中,有6种手性化合物能得到较好的分离,表现出较好的手性分离性能．并且手性固定相之间具有较好的互补性．     

A new method for in situ crosslinking of stationary phases on fused silica capillary columns

A new mixed crosslinking agent composed of dicumyl peroxide and tetra(methylvinyl)cyclotetrasiloxane was used to prepare fused silica capillary columns with in situ crosslinked stationary phases including PEG-20M, SE-54, and OV-1. These columns proved to have good thermostability and inertness. As examples of potential applications a mixture of isomers of nitrotoluene and dinitrotoluene, and pyrolyzates of polystyrene were separated by using these columns.     

Chiral covalent organic framework incorporated organic polymer monolithic capillary column for enantioseparations

A chiral covalent organic framework was synthesized, characterized, and incorporated into organic polymer monolithic capillary columns to provide chiral stationary phases for enantioseparations. The prepared monolithic capillary columns were characterized by scanning electron microscopy and elemental analysis. To obtain better enantioseparations, the columns’ preparation conditions, and enantioseparation conditions were optimized. Baseline resolutions of several chiral compounds were obtained with good reproducibility and stability. Furthermore, the mechanism of chiral recognition was investigated using molecular docking with AutoDock. Docking results showed that the enantioselectivity factor rather than resolution is correlated with the binding free energy difference between enantiomers with the chiral covalent organic framework. And abundant acetoxy and nitrile groups as well as benzene rings in the chiral covalent organic framework are responsible for the enantioseparation ability of the chiral monolithic capillary columns.     

Expanding the Applications of the Ionic Liquids as GC Stationary Phases: Plasticizers and Synthetic Musks Fragrances

The exceptional properties of the ILs make them ideal for gas chromatography stationary phases. New stationary phases exhibiting good separation selectivity, high efficiency, and high thermal stability are in high demand. Recently, several gas chromatographic capillary columns containing IL stationary phases of various polarities have been introduced on the market. The aim of this work is to extend the applications of the ILs as GC column coatings. The effectiveness of five different commercial IL columns (SLB™-IL59, SLB™-IL76, SLB™-IL82, SLB™-IL100 and SLB™-IL111) for the analysis of two different families of emerging contaminants of environmental concern (plasticizers and synthetic musk fragrances) has been explored. The results obtained for these two families of compounds are compared with the ones obtained when using a (5 %-phenyl)-methylpolysiloxane column. For three of these IL columns, applications have not yet been described. Good resolution for the most of the studied emerging pollutants belonging to five different analytical groups (adipates, phthalates, macrocyclic musks, nitromusks and polycyclic musks) was achieved in all the IL columns.

     

气相色谱研究杯[4]芳烃衍生物

选取两种不同结构的怀「４」芳烃做固定相，研究了烃基取代苯，不同数目的甲基取代苯，稠环芳烃和醇系列化合物的保留值变化规律；讨论了杯「４」芳烃固定相与溶质分子间的弥散力作用，氢键作用及空间适应性；指出杯「４」芳烃对芳香烃等良好选择性；对乙腈和甲醇等小分子似有包结。     

Monolithic bed structure for capillary liquid chromatography

Monolithic stationary phases show promise for LC as a result of their good permeability, ease of preparation and broad selectivity. Inorganic silica monoliths have been extensively studied and applied for separation of small molecules. The presence of a large number of through pores and small skeletal structure allows the chromatographic efficiencies of silica monoliths to be comparable to columns packed with 5 μm silica particles, at much lower back pressure. In comparison, organic polymeric monoliths have been mostly used for separation of bio-molecules; however, recently, applications are expanding to small molecules as well. Organic monoliths with high surface areas and fused morphology rather than conventional globular morphology have shown good performance for small molecule separations. Factors such as domain size, through-pore size and mesopore size of the monolithic structures have been found to govern the efficiency of monolithic columns. The structure and performance of monolithic columns are reviewed in comparison to particle packed columns. Studying and characterizing the bed structures of organic monolithic columns can provide great insights into their performance, and aid in structure-directed synthesis of new and improved monoliths.     

A simple cladding process to apply monolithic silica rods in high performance liquid chromatography

A simple cladding procedure was developed to apply monolithic silica rods in chromatography. This was used to evaluate the performances of new monolithic silica phases synthesised using a triblock copolymer as a phase separation inducer. The cladding procedure is found efficient after several tests, including scanning electron microscopy and mercury porosimetry, and the obtained columns present a relatively good efficiency in adsorption chromatography (H min is about 50 μm) as compared to other lab-scale developed columns.     

Influence of the unpacked section on the chromatographic performance of duplex strong anion-exchange columns in capillary electrochromatography

This work describes initial investigations of strong anion-exchange (SAX) packing materials for capillary electrochromatography (CEC). The use of SAX phases in CEC is theoretically appealing for the analysis of negatively charged species. The reversed direction of the electroosmotic flow (EOF) generated by SAX phases (in comparison to reversed phases and strong cation-exchange phases) means that negative species can migrate with the EOF, not against it, hence the analysis times, of such species should be decreased and efficiencies improved. Duplex CEC columns (the standard for instruments using UV detection) consist of a packed and an unpacked section. Using common reversed-phase packing materials the direction of the EOF in both sections is co-linear, however when normal fused-silica capillaries are packed with SAX material the direction of the EOF in the two sections oppose one another. It has been shown, using conventional duplex CEC columns and fully packed CEC-MS columns that the opposing direction of EOF causes a massive degradation in column performance. Consequentially, it is demonstrated that if the EOF in the open section of the duplex SAX column can be controlled via pH or capillary derivatisation then good, reproducible CEC can be performed on anionic species using SAX packed CEC columns.     

A new type of triptycene-based stationary phases with alkylated benzimidazolium cations for gas chromatographic separations

The new type of triptycene-based stationary phases with alkylated benzimidazolium cations shows high selectivity towards aromatic isomers.     

溶胶-凝胶法制备四种环糊精衍生物毛细管气相色谱柱

采用溶胶-凝胶法制备了七(2,3,6-三-O-乙基)-β-环糊精(全乙基-β-CD)、七(2,3,6-三-O-丙基)-β-环糊精(全丙基-β-CD)、七(2,3,6-三-O-辛基)-β-环糊精(全辛基-β-CD)和2,6-二-O-苄基-β-CD 4种环糊精衍生物毛细管气相色谱柱。在制备方法上,仿照一般动态法,大大简化了制备过程,缩短了制备时间。所得色谱柱的理论塔板数在3000/m左右,能够很好地分离苯衍生物的位置异构体,尤其对难分离的二甲苯、甲酚等取得了理想效果(α＞1),其中溶胶-凝胶法制备的全烷基(乙基、丙基、辛基)化环糊精衍生物柱的分离能力优于2,6位苄基衍生化的环糊精柱。 同一根柱不同次进样和不同柱之间表现出良好的重复性,保留时间的相对标准偏差小于8.5%;对使用大约40次后的溶胶-凝胶柱重新进行测试,柱效下降不明显,说明该类色谱柱的稳定性良好。     

冠醚修饰型手性固定液的合成及其气相色谱性能的研究

合成了两种含冠醚功能基的手性固定液：（１Ｓ,２Ｓ）－１－对硝基苯基－２－（４＇－西佛碱基苯并１５－冠－５）－丙烷－１,３－烯丙氧基聚硅氧烷和３－甲基－２－（４＇－甲酰胺－苯并１５－冠－５）－丁酸乙酯。用它们涂制的石英毛细管柱呈强极性,色谱性能良好。并探讨了固定液的结构对分离能力的影响。     

Review of recent advances in the preparation of organic polymer monoliths for liquid chromatography of large molecules

In recent years the use of monolithic polymers in separation science has greatly increased due to the advantages these materials present over particle-based stationary phases, such as their relative ease of preparation and good permeability. For these reasons, these materials present high potential as stationary phases for the separation and purification of large molecules such as proteins, peptides, nucleic acids and cells. An example of this is the wide range of commercial available polymer-based monolithic columns now present in the market.     

Recent developments in the field of monolithic stationary phases for capillary electrochromatography

This review summarizes the contributions to the rapidly growing area of monolithic columns based on both silica and synthetic polymers for capillary electrochromatography and chip electrochromatography, with a focus on those published during the year 2004. A wide variety of both modified approaches to the "old" monoliths and new monoliths have been reported despite the very short period of time covered. This demonstrates that monolithic stationary phases have become a well-established format in the field of electrochromatography. The simplicity of their preparation as well as the good control over their porous properties and surface chemistries make the monolithic separation media an attractive alternative to capillary columns packed with particulate materials.     

Investigation of poly[oligo(ethylene glycol)diacrylates] as potential stationary phases in GC

Poly[oligo(ethylene glycol)diacrylate]s were investigated as potential candidates for application as stationary phases in capillary gas chromatography. Depending on the molar mass of the monomer, up to three different phase transitions were observed in calorimetric scans of the polymers. Two transitions have been identified as the glass transition and melting of crystallites while the nature of the third effect remains unknown. The new stationary phases demonstrate a good separating ability and selectivity in the viscous‐elastic state, i.e. at temperatures above the glass transition and melting points. The new polymeric stationary phases possess selectivity similar to conventional PEG columns but provide better thermal stability than conventional PEG stationary phases.     

涂渍极性及强极性固定相硅膜改性弹性玻璃毛细管柱的研制

本文工作研究了极性、强极性固定液直接涂渍在硅膜改性弹性玻璃毛细管内壁上，经优化温度老化色谱柱，成功地研制出ＯＶ－２２５，ＤＥＧＳ，Ｓｉｌａｒ５，Ｓｉｌａｒ９，Ｓｉｌａｒ１０等硅膜改性弹性玻璃毛细管柱，各种柱子均具有柱效高，热稳定性好的色谱性能。     

Polymeric monolithic stationary phases for capillary electrochromatography

This review summarizes the contributions of a number of groups working in the rapidly growing area of monolithic columns for capillary electrochromatography (CEC), with a focus on those prepared from synthetic polymers. Monoliths have quickly become a well-established stationary phase format in the field of CEC. The simplicity of their in situ preparation method as well as the good control over their porous properties and surface chemistries make the monolithic separation media an attractive alternative to capillary columns packed with particulate materials. A wide variety of approaches as well as materials used for the preparation of the monolithic stationary phases are detailed. Their excellent chromatographic performance is demonstrated by numerous separations of different analytes.     

Temperature and pH‐stability of commercial stationary phases

In this paper, the temperature and pH stability of silica‐based RP stationary phases were investigated. Furthermore, nonsiliceous phases like a polymeric column based on polystyrene divinylbenzene and a polybutadiene coated zirconium dioxide column were also included. The columns were heated up to 150°C at dynamic conditions, which means that the eluent consisting of water and methanol (90:10, v/v) was continuously purged through the packed bed. After every 5 h, the columns were cooled down to room temperature and the efficiency was measured by injecting a test sample based on the Neue test. It could be shown that some stationary phases exhibited a very good temperature stability at the test conditions specified above.