十四烷基胺键合固定相的反相色谱性能

制备了一种新型反相液相色谱固定相──十四烷基胺硅胶键合固定相。以甲醇和水为二元流动相,评价了该固定相的疏水性、选择性和残留硅醇基活性。同时分离了包括碱性、酸性和中性有机化合物在内的混合物。结果表明,在该固定相上,碱性化合物的色谱峰对称性较好,硅酸基活性受到抑制,并具有良好的选择性。     

Survey and Trends in the Preparation of Chemically Bonded Silica Phases for Liquid Chromatographic Analysis

In order to increase chromatographic selectivity and to extend the analytical capability of reversed phase liquid chromatography (RP HPLC) many investigators have concentrated on the preparation of silica based column packings with chemically bonded phases (CBP). These phases have also been successfully used in sample preparation techniques, mainly in solid phase extraction (SPE). Although alkyl bonded phases (e.g., C₂, C₈, and C₁₈) are the most widely used packings in RP HPLC and SPE, various specific applications require CBPs with polar functional groups (e.g., -NH₂, -NO₂, -CN, and/or -OH). The solution of problems with separation of complicated chiral compounds was attempted by applying stationary phases with chiral selectors (e.g., cyclodextrins, Pirkle phases, crown ethers, etc.). On the other hand, packings with pseudo-membrane or liquid crystal properties have been utilized for the separation of various substances of natural origin. Porous silica is commonly used as a support in the preparation of CBPs. Its physico-chemical characteristics, such as: type and structure of siliceous matrix, porosity, type and concentration of silanol groups, as well as surface purity, strongly influence the density and structure of chemically bonded phases. Recognition of these properties is helpful in optimizing separation processes based on RP HPLC elution and/or extraction of substances with polar character.     

氮杂冠醚键合固定相的RP-HPLC色谱性能研究

报道在硅胶表面进行固-液相反应合成的3-(氮杂-18-冠-6)丙基键合固定相对金属离子的络合能力和色谱性能,研究了流动相组成、pH值、金属离子对极性二取代苯保留值的影响,探讨色谱分离机理。这种键合相通过对金属离子的络合,显示多种色谱分离机理,对极性二取代苯异构体分离选择性、分析速度均优于对比的C₁₈键合固定相反相色谱。     

The Characterisation of Chemically Bonded Chromatographic Stationary Phases by Thermogravimetry

This paper details a simple thermogravimetric procedure to determine the amount of ligand present on silica based chemically bonded stationary phases for HPLC and CEC. The weight loss observed from stationary phases between 150 and 600 °C was found to be directly proportional to carbon loading of the phase. Weight loss at lower temperatures was due to the removal of weakly bound solvent. The use of temperatures higher than 600 °C resulted in the condensation of surface silanol groups resulting in an artificially elevated carbon loading result. The procedure has been applied to a range of commercially available HPLC stationary phases and the results obtained for the carbon loading for each phase was within 3% of the value reported by the manufacturer. The data presented demonstrates that the procedure is accurate and precise over a rage of carbon contents typically observed for commercially available HPLC phases and is applicable to a range of silica supports and hydrophobic ligands.     

一种新型液相色谱屏蔽键合相的色谱性能

烷基硅胶键合固定相 ,特别是十八烷基键合固定相 ,是应用最广泛的反相色谱固定相 ,改变流动相组成 ,就可实现大多数有机化合物的分离分析 .但是 ,由于硅胶表面残留硅醇基的存在 ,分离某些极性化合物 ,特别是碱性有机化合物时使色谱峰变形拖尾 ,灵敏度下降 .采用封端技术也不能完全消除残留硅醇基的影响 .在分离碱性物质时大都采用缓冲溶液流动相 ,长期使用缓冲溶液将影响仪器和色谱柱的性能和寿命 .近年来 ,为了改善碱性化合物的分离 ,提出了空间保护相 [1] 和烷基酰胺屏蔽相 [2 ,3] .依据静电屏蔽原理 ,我们 [4 ]曾制备了十四烷基胺反相色…     

高效液相色谱烷基硅胶键合固定相

综述了高效液相色谱烷基硅胶键合固定相研究的最新进展,参考文献４０篇。     

高效液相色谱环糊精键合固定相

环糊精是由Ｄ（＋）－葡萄糖单元通过α－１，４糖苷键连接的环状齐聚糖，其最典型的性质是能与许多客体分子形成包容配合物。高效液相色谱环糊精键合固定相广泛用于对映异构体，非对映异构体，结构异构体和常规化合物的分离。     

十八碳键合钛胶固定相的制备及其色谱性能

 以聚合诱导胶体凝聚法 (PICA)合成的窄粒径分布的TiO2 多孔微球 (表面积 :3 6 7m2 /g ,孔容 :0 3 0mL/g ,平均孔径 :3 2 2nm ,平均粒径 :3 5 μm)为基质 ,与十八碳三甲氧基硅烷的甲苯溶液共同回流 8h ,制得十八碳键合钛胶固定相 (ODT)。该固定相的含碳量为 2 87% (即 0 66μmol/m2 ) ,疏水选择性为 0 4 63 8。将其用于分离中性和碱性化合物时 ,显示出比较好的色谱性能。     

Preparative Hydrophobic Interaction Chromatography of Proteins Using Ether Based Chemically Bonded Phases

Abstract

This paper examines the use of 15–20 micron wide-pore silica-based ether bonded phases for the preparative hydrophobic interaction chromatography of proteins. In particular, silyl ethers are immobilized on large particle silica in an analogous manner to previously developed ether bonded 5 um analytical supports. The preparative supports are reproducibly prepared and exhibit constant chromatographic retention for at least five months of continual use. Preparative columns can be operated for protein chromatography with peak shapes and capacity as predicted by the Snyder gradient elution model. Moreover, similar retention times are obtained relative to those on the 5 um analytical columns, enabling the direct transition and scale-up of separation. Gradient optimization is seen to directly parallel that performed on 5 um bonded ether analytical columns. Acceptable chromatographic resolution was obtained with sample capacity of >15 mg protein/ml column volume using a repetitive injection technique. A column clean-up strategy is examined for rapid and safe removal of contaminants. An illustrative example of use of the bonded ether preparative columns is made by application to soybean trypsin inhibitor purification. Initial results are presented on a column-switching method for the analytical monitoring of preparative separation.     

A Geometrical Model for Chemically Bonded TMS and PDS Phases

Abstract

A geometrical model is developed for monomeric TMS and PDS phases that are chemically bonded to silica. Using experimental data for maximum surface coverage and considering amorphous silica as a collection of distorted crystals, we calculate that each nm² of the silica surface contains 2.3 modified hydroxyl groups, 1.3 free hydroxyl. groups and 0.6 pairs of bonded hydroxyl groups, respectively. From the dimensions of the silane molecule it is concluded that for maximum coverage the TMS and PDS molecules are rigidly attached to the silica surface with an Si-O-Si bond angle between 120 and 140 degrees. The unreacted hydroxyl groups are not completely screened but will be quite inaccessible on either phase. Very little free surface area remains on the silica surface.     

Cyclodextrin Bonded Phase for Liquid Chromatographic Separation and Analysis of Some Oral Contraceptives

Abstract

A specific and sensitive analytical HPLC procedure was described for quantitative determination of ethinylestradiol and norethisterone acetate (Anovlar 1) and ethinylestradiol and norgestrel (Primovlar) in tablet formulation. These steroids were extracted from the tablets with methanol. The steroids were then determined with high performance liquid Chromatograph-Cyclobond 1 column using mobile phase phosphate buffer pH 7.0: methanol (60:40), flow rate 0.5 ml min^?1 and the detection was effected spectrophotometrically at 280 nm, using variable wavelength UV detector.

There was > 99.3% recovery from synthetic mixtures and the coefficient of variation was < 2.0% for the formulations investigated. The method is highly quantitative and reproducible.     

键合型纤维素—苯基氨基甲酸酯手性固定相的制备及用于对映异构？…

采用化学键合法,利用４,４′－二苯基甲基二异氰酸酯作间隔臂,通过纤维素葡萄糖单元上２、３或６－位上的羟基将纤维素衍生物键合在氨丙基硅胶上,制备了键合型纤维素－苯基氨基甲酸酯手性固定相。同时,以微晶纤维素和苯基异氰酸酯为原料,合成了纤维素－三苯基氨基甲酸酯,并以未修饰的硅胶为载体,制备了涂敷型纤维素－三苯基氨基甲酸酯手性固定相。分别对键合型和涂敷型两类手性固定相进行了表征,并首次在纤维素－苯基氨基甲     

键合型纤维素-苯基氨基甲酸酯手性固定相的制备及用于对映异构体拆分

采用化学键合法,利用4,4′-二苯基甲基二异氰酸酯作间隔臂,通过纤维素葡萄糖单元上2、3或6-位上的羟基将纤维素衍生物键合在氨丙基硅胶上,制备了键合型纤维素-苯基氨基甲酸酯手性固定相.同时,以微晶纤维素和苯基异氰酸酯为原料,合成了纤维素-三苯基氨基甲酸酯,并以未修饰的硅胶为载体,制备了涂敷型纤维素-三苯基氨基甲酸酯手性固定相.分别对键合型和涂敷型两类手性固定相进行了表征,并首次在纤维素-苯基氨基甲酸酯手性柱上拆分了安息香.     

Evaluation of Mobile and Stationary Phases in Reversed-Phase High-Performance Liquid Chromatography of Conjugated Bile Acids

Abstract

The reversed-phase high-performance liquid chromatographic separation of the ten major conjugated bile acids of man using isocratic conditions is described. Each component of the mobile and stationary phases was examined for its ability to influence the separation selectivity. Manipulation of pH, buffer species, organic modifier and different types of packings showed that optimal resolution was obtained with a mobile phase of methanol-0.02M sodium acetate (60:30) adjusted to pH 4.2 with phosphoric acid, on a Supelcosil LC-18-DB column. Advantages of the optimized phase system are the complete baseline separation of compounds within a short period of time, improved peak symmetry and a high rate of reproducibility. This new chromatographic method, coupled with UV detection at 205 nm, is suitable for the simultaneous determination of bile acid conjugates in routine clinical analysis.     

混合型烷基键合硅胶液相色谱固定相的合成与性能评价

多环芳烃;取代基位置异构体;混合型烷基键合硅胶液相色谱固定相的合成与性能评价     

苯胺甲基键合固定相的合成和色谱性能

多环芳烃;色谱法;苯胺甲基键合固定相的合成和色谱性能     

反相高效液相色谱法制备纯化大豆异黄酮糖苷

利用制备高效液相色谱法从大豆总异黄酮提取物中制备出了3种大豆异黄酮糖苷。在Nova-Pak HR C18色谱柱(100 mm×25 mm i.d.,6 μm)上,以甲醇-体积分数为0.1%的乙酸水溶液(体积比为23∶77)为流动相,流速为20 mL/min,采用 等度洗脱方式,制备了3种大豆异黄酮糖苷,经质谱分析,确认它们分别为大豆苷、黄豆苷和染料木苷。高效液相色谱分析 表明,所制备的3种化合物的纯度均达到了99%以上。     

Experimental Study of Model Bonded Stationary Phases for Liquid Chromatography I. Silica/Polyethyleneoxide

Abstract

Model bonded phases have been prepared by reaction of polyethyleneoxide of various molecular weights (200 < M < 5.10⁶) on silica.

The retention behavior of solutes on these bonded stationary phases for liquid chromatography depends on silica loadings, grafted molecule length, solute size and solvent nature. Different mechanisms such as dissolution effect in the grafted phase, adsorption on mineral support and steric exclusion due to the residual porosity of silica, are involved in the observed separations. An expression of elution volumes in relation with these mechanisms is proposed.

Chromatographic data and thermodynamic predictions are in good agreement.     

Experimental Study of Model Bonded Stationary Phases for Liquid Chromatography II. Silica/Polystyrene

Abstract

Mechanisms of separations performed on bonded phases in liquid chromatography are investigated by studying model grafted phases.

These phases are prepared by reaction of chlorinated silica with living anionic polystyrene of various molecular weights. Owing to thermodynamic predictions, an expression of the elution volume of various solutes on such packings and conditions for reverse-phase chromatography are proposed.