HPLC Separation of Different Groups of Small Polar Compounds on a Novel Amide-Embedded Stationary Phase

Retention behaviors of an amide-embedded silica base stationary phase, which was recently developed by our group, were studied by using six different groups of small polar compounds including phenolic compounds, substituted anilines, chlorinated herbicides, Sudan dyes and some nucleotides and nucleosides in HPLC. The chromatographic behaviors of the prepared stationary phase for these analytes were compared with those of a commercially available reversed-phase column ACE C18 under same conditions. Among the six groups of analytes studied, the amide-silica stationary phase showed enhanced selectivity towards phenolic compounds, substituted anilines, Sudan dyes and herbicides under reversed-phase conditions and satisfactory selectivity towards nucleosides and nucleotides which could not be separated with ACE C18 column under HILIC conditions. Experimental data provided some evidence that functional groups on the stationary phases might have certain degrees of influence on selectivity possibly through secondary interactions with the model compounds. The retentions of the moderately polar compounds such as phenolic acids, anilines and herbicides on the stationary phase are higher than highly polar compounds such as nucleotides and nucleosides due to both the hydrophobic and hydrophilic interactions between the stationary phase and analytes. The quantitative determination of Sudan dyes (I, II, III, and IV) in red chilli peppers was performed. Many red chilli peppers were screened and three of them contained Sudans dyes.     

“包埋”极性官能团固定相对碱性化合物分离的热力学研究

以苯、吡啶、尼古丁和普鲁卡因为探测因子，考察了酰胺型、胺型、醚型和酯型4种“包埋”极性官能团的新型键合固定相对碱性化合物在流动相pH值分别为3．0和7.0时的热力学焓变。实验结果表明，新型固定相由于烷基分子链中“嵌入”极性官能团，因此在流动相pH为3．0时温度对碱性溶质的保留影响相互差异较大。在流动相pH为7．0时，根据Van＇t Hoff方程计算出4种待测物质从流动相转移到固定相上的△H^0，从△H^0的绝对值大小、相关系数以及实际的分离效果可以发现，在分离强碱性物质时，若实验条件一样，则分离效果是酰胺型和胺型〉酯型固定相〉醚型固定相，但它们均优于传统的固定相。     

“包埋”极性官能团固定相对碱性化合物分离的热力学研究

以苯、吡啶、尼古丁和普鲁卡因为探测因子,考察了酰胺型、胺型、醚型和酯型4种"包埋"极性官能团的新型键合固定相对碱性化合物在流动相pH值分别为3.0和7.0时的热力学焓变.实验结果表明,新型固定相由于烷基分子链中"嵌入"极性官能团,因此在流动相pH为3.0时温度对碱性溶质的保留影响相互差异较大.在流动相pH为7.0时,根据Van′t Hoff方程计算出4种待测物质从流动相转移到固定相上的ΔH0,从ΔH0的绝对值大小、相关系数以及实际的分离效果可以发现,在分离强碱性物质时,若实验条件一样,则分离效果是酰胺型和胺型＞酯型固定相＞醚型固定相,但它们均优于传统的固定相.     

姜黄素键合硅胶固定相HPLC分离碱性化合物

反相高效液相色谱法;姜黄素键合硅胶固定相;碱性化合物;色谱保留机理     

Retention Behavior of Some Compounds Containing Polar Functional Groups on Perfluorophenyl Silica-Based Stationary Phase

A retention study on perfluorophenyl silica-based stationary phase was undertaken for some organic compounds containing different polar functionalities. The dependence of the retention factor on the content of organic modifier (acetonitrile, or methanol) in mobile phase was fitted by polynomial equations. The only exception was observed for adenine, which showed a sigmoidal dependence for the retention factor versus organic modifier content. The extrapolated values of retention factor for water as mobile phase (log k _w) from these dependences were well correlated with octanol–water partition constants (log K _ow), excepting the values for hexachlorocyclohexane isomers and adenine. Temperature dependences of the retention factor obeyed the van’t Hoff equation with thermodynamic parameters similar to those obtained in reversed phase on C8 or C18 stationary phases, excepting two statines whose dependences of ln k on the reciprocal value of absolute column temperature were nonlinear. Again, adenine had an atypical behavior with decrease in the retention factor with the increase in column temperature, due to possible tautomeric equilibria of this compound in presence of water, in accordance with theoretical models reported by literature. Charge modeling with MarvinSketch package program revealed charged centers from analyte molecule that could interact differently with charge centers from stationary phase.     

二氢麦角碱在极性嵌入反相色谱固定相上的分离行为

二氢麦角碱的4种组分具有不同的药效特性,需适当的分析方法对其在不同剂型药品中的含量进行分析.传统液相色谱方法使用强碱性流动相,严重腐蚀硅胶基质色谱填料,影响色谱柱寿命.合成了极性嵌入反相固定相--C18酰胺固定相,并在中性流动相条件下分离4种组分.考察了流动相组成和pH对二氢麦角碱在C18酰胺固定相上保留行为的影响.在150 mm×4.6 mm I.D.的C18酰胺色谱柱上,流动相为乙腈-20 mmol/L Na2HPO4(30:70,V/V,pH 7.0)的条件下实现了4种组分的基线分离.与传统方法相比,极性嵌入反相固定相可以有效的改善碱性化合物的分离特性和大幅度地延长色谱柱的使用寿命.     

醋酸纤维素液相色谱固定相的制备与手性拆分

在均相条件下合成了醋酸纤维素,将其涂渍在修饰硅胶表面,制备了涂渍型高效液相色谱固定相.在40MPa压力下将所得固定相装入色谱柱.在高效液相色谱正相色谱条件下,对包括醇类、羧酸类、胺类、氨基酸类及药物类的16种新型手性化合物进行了拆分试验,结果有6种手性化合物得到了分离,效果良好.     

正反相模式下键合纤维素手性固定相对手性化合物的拆分

在自行合成的键合型纤维素-(3,5-二甲基苯基氨基甲酸酯)(CDMPC-CSP)手性固定相上,在正相模式下对苯偶姻和甲霜灵外消旋体进行了拆分,考察了流动相中醇以及温度在手性识别中对手性分离的影响。同时考察了反相模式下外消旋体的拆分。     

Selective Separation of Polar Compounds Using an Electric Field Coupled Normal Phase HPLC Column

Abstract

An electric field coupled method for separation of polar compounds using normal phase high performance liquid chromatography is described. The method, which is not based on electrophoresis or electrochromatography, selectively changes the column capacity for polar analytes. The use of different columns showed improved column efficiency and up to a 62% increase in the number of theoretical plates. The theory for the improvement is presented. The significance and utility of the method for selective analysis of polar fractions in environmental samples is discussed.     

高效液相色谱纤维素衍生物类手性固定相拆分泮托拉唑对映体

泮托拉唑（pantoprazole,简称为PAN）是一种选择性的长效质子泵抑制剂。PAN分子由苯并咪唑通过亚砜基连接吡啶环组成,内含手性硫原子,故存在S-（-）型和R-（＋）型对映异构体,临床以消旋体给药。文献已有用牛血清白蛋白、卵粘蛋白、多糖衍生物和α1-糖蛋白、酒石酸衍生物等手性固定相拆分泮托拉唑对映体的报道。纤维素-三-（4-甲基苯甲酰酯）手性固定相稳定性好,柱效高,对羰基化合物、内酯、内酰胺、亚砜等化合物有较好的拆分能力,硫巴比妥衍生物、痛力克等药物都在该固定相上得到了完全分离。本文使用纤维素-三-（4-甲基苯甲酰酯）手性固定相实现了泮托拉唑对映体的拆分,并计算了对映体的光学纯度。     

Stationary Phases 21: A New Polar Substituted Triazine Stationary Phase for HPLC

A method for preparing a new polar substituted triazine stationary phase is described. The structure of the triazine phase on silica was characterized by elemental analysis, and by FTIR, solid state FT-¹³C NMR, and ²⁹Si NMR spectral analysis. The chromatographic properties of this packing material have been evaluated by using a number of different solutes, and the properties compared with those of a commercial stationary phase RP-18. It is found that this triazine phase has weak π-donor ligands on the silica surface.     

纤维素类手性固定相高效液相色谱法拆分三唑类手性化合物

采用纤维素-三(3,5-二甲基苯基氨基甲酸酯)手性固定相(Chiralcel OD)和纤维素-三(4-甲基苯基甲酸酯)手性固定相(Chiralcel OJ),在正相高效液相(N-HPLC)模式下,基线拆分了两个系列共13个结构类似的三唑类手性化合物,结果发现,当手性固定相(Chiral Stationary Phase,CSP)可以与溶质分子之间形成较强氢键时,Chiralcel OD的手性识别能力明显优于Chiraleel OJ,当手性固定相(CSP)与溶质分子之间不能或难于形成氢键时,两种CSP的手性拆分能力相似;提高流动相中极性改性剂的极性有利于手性化合物的拆分。在反相高效液相(R-HPLC)模式下,共基线拆分了8个三唑类手性化合物,实验发现,OJ-CSP的手性拆分能力明显优于OD-CSP．它们对对映体分子的选择性主要受CSP与溶质分子间的π-π相互作用的影响。     

Preparation of a Novel Stationary Phase for Separation of Ethylbenzene Hydroperoxides

The novelty of this work is preparation of a special stationary phase for selective separation of hydroperoxides. This column can be used widely in the polymerization industries where a variety of initiators (mainly the hydroperoxides) are used. In this work, the ionic liquid-based silica particles were prepared and used as a novel stationary phase for separation of ethylbenzene hydroperoxides. The mobile phase of methanol/acetonitrile from 90:10 to 70:30 (v v^?1) was used to separate three isomers of ethylbenzene hydroperoxide. A satisfactory linearity was obtained from 1.0 to 110.0 mg mL^?1 (RSD <4.0 %). The stationary phase performed stably and produced reproducible results, highlighting its potential as a separation material.     

Selective Separation of Polar Unsaturated Organics Using a Water Stationary Phase in Gas Chromatography

Chromatographia - A water stationary phase is explored as a novel means of selectively separating unsaturated analytes in gas chromatography. Several unsaturated/saturated analyte pairs consisting...     

Polymeric Functionalized Stationary Phase for Separation of Ionic Compounds by IC

Synthesis and properties are described of multilayered stationary phases containing quaternary amine functional groups used for the analysis of inorganic anions by ion chromatography. The bonded phases were characterized by elemental analysis, solid state (13)C NMR spectroscopy and chromatographic methods. The surface of polyhydroxyethyl methacrylate (solid support) was coated with polymeric layers formed by condensation polymerization of primary amine with diepoxide. Each layer of the anion exchange stationary phase consisted of methylamine and 1,4-butanedioldiglycidyl ether copolymer. A series of stationary phases with different number of polymerized layers were tested. Separation of inorganic anions, such as F(-), Cl(-), NO(2) (-), Br(-), NO(3) (-), were performed. Aqueous hydroxide, carbonate and bicarbonate solutions were used as mobile phases.     

酸性化合物在十二胺-N,N-二亚甲基膦酸改性氧化锆固定相上的分离

酸性化合物在十二胺-N; N-二亚甲基膦酸改性氧化锆固定相上的分离;氧化锆;色谱固定相;十二胺-N; N-二亚甲基膦酸     

Chromatographic Separation on Silica of Polar Aromatic Compounds

Abstract

Our goal in this work, was to seek the best experimental conditions which allow the migration and partition in thin layer chromatography of numerous aromatic compounds, essentially those of polar character, according to a predominating adsorption process. We then studied the modification of different coefficients intervening in these chromatographies according to accepted experimental conditions. The results with different modes of adsorbent deactivation show that the adsorption process is possible and must be interpreted by the SNYDER Model.     

Synthesis and Chromatographic Evaluation of Perfluorooctyl Stationary Phase for Separation of Basic Compounds

Fluorinated stationary phases provide unique separation effect on basic compounds, due to the fluorine atoms, and pentafluorophenyl stationary phases (PFPs) are the most widely used. Considering that some fluoroalkyls have higher fluorine contents than PFPs do, it is speculated that fluoroalkyl stationary phases should have potential new applications. Herein, we synthesized a silica-based stationary phase bonding perfluoroctyl (FC8) proved by characterization through elemental analysis and solid-state ¹³C cross-polarization/magic-anglespinning nuclear magnetic resonance. The chromatographic behavior of the stationary phase was evaluated with test compounds. In addition, to further study the applicability of FC8 materials, Corydalis decumbens (Thunb.) Pers. fraction, considered as a challenging medicine on reversed-phase chromatography columns, was chosen as a test sample. Results demonstrated that the FC8 stationary phase had better and more satisfactory separation performance than the PFP stationary phase on basic compounds.

     

芘基丁酸键合硅胶固定相对含π电子物质的高效液相色谱分离研究

通过芘基丁酸键合硅胶固定相对含π电子物质的分离研究, 考察了该固定相的色谱性能. 结果表明, 该固定相不仅具有疏水作用和电荷转移性能, 还具有很强的平面识别能力, 可很好地分离烷基苯、 稠环芳烃及取代硝基苯等各种含π电子物质， 且在pH 3.5～7.0 时化学稳定性能良好, 硅醇基效应得到了很好的抑制, 可有效地用于碱性化合物的分离分析.     

万古霉素手性固定相分离曼尼希碱类化合物对映体

采用大环抗生素类万古霉素手性固定相高效液相色谱法研究了一系列曼尼希碱类化合物的手性分离情况,并讨论了流动相中有机相的种类和比例、缓冲盐的种类和浓度、pH和柱温对该类化合物手性分离的影响。最佳实验条件为:乙腈:硝酸铵(35mmol/L,pH3.8)=15∶85(V/V),柱温15℃,流速0.6mL/min,检测波长300nm;四氢呋喃:硝酸铵(20mmol/L,pH4)=15∶85(V/V),柱温15℃,流速0.6mL/min,检测波长350nm。通过对比研究8种曼尼希碱类化合物的色谱行为,从结构上讨论了化合物中各种官能团对手性分离的影响,并探讨了手性分离的内在机制。