{"title":"Retention and Selectivity on Hydrophilic Interaction Liquid Chromatography Columns Modified with Polyethylene Glycol of Different Chain Length","authors":"Yuqian Xiang, Yu Huang, Xiaohui Yan, Zhipeng Zhu, Dapeng Wu, Peng Gao, Jiulong Li","doi":"10.1007/s10337-024-04363-7","DOIUrl":null,"url":null,"abstract":"<div><p>In this work, in order to investigate retention and selectivity mechanism on hydrophilic interaction liquid chromatography (HILIC), one of the most common hydrophilic stationary phases, polyethylene glycols (PEG) of different molecular weights (200, 400, 800 and 2000 Dalton) were covalently bonded to porous silica spheres via isocyanate silane. The PEG stationary phase was then characterized in detail by infrared spectroscopy, scanning electron microscope, nitrogen adsorption–desorption isotherms, and thermogravimetric analysis, and the PEG bonding density was determined as 2.7, 2.3, 1.4, 0.26 μmol m<sup>−2</sup>, respectively. The HILIC retention mechanism was systematically conducted by quantitative evaluation of the effect of partitioning and adsorption, hydrogen bonding and hydrophilicity, and temperature on the retention of nucleosides and nucleobases. It was found that the retention was highly relevant on the partitioning, hydrogen bonding between solutes and PEG, and strong electrostatic interactions (attractive/repulsive) between solutes and silica. To further assess the separation performance, three kinds of polar compounds (nucleosides and nucleobases, organic acids and β-blockers) were chosen as probe compounds. Among the four PEG stationary phases, it was found that the higher PEG ligand density generally resulted into more superior separation performance to these polar compounds, that is, PEG200-bonded stationary phase with highest ligand density of 2.7 μmol m<sup>−2</sup> generated better resolution. Furthermore, higher ligand bonding mass would increase the retention of nucleosides, nucleobases and organic acids except β-blockers. Generally, the HILIC stationary phase with continuous and dense hydrophilic layer is beneficial to the separation of polar analytes.</p><h3>Graphical Abstract</h3>\n<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":518,"journal":{"name":"Chromatographia","volume":"87 10","pages":"661 - 673"},"PeriodicalIF":1.2000,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Chromatographia","FirstCategoryId":"92","ListUrlMain":"https://link.springer.com/article/10.1007/s10337-024-04363-7","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"BIOCHEMICAL RESEARCH METHODS","Score":null,"Total":0}
引用次数: 0
Abstract
In this work, in order to investigate retention and selectivity mechanism on hydrophilic interaction liquid chromatography (HILIC), one of the most common hydrophilic stationary phases, polyethylene glycols (PEG) of different molecular weights (200, 400, 800 and 2000 Dalton) were covalently bonded to porous silica spheres via isocyanate silane. The PEG stationary phase was then characterized in detail by infrared spectroscopy, scanning electron microscope, nitrogen adsorption–desorption isotherms, and thermogravimetric analysis, and the PEG bonding density was determined as 2.7, 2.3, 1.4, 0.26 μmol m−2, respectively. The HILIC retention mechanism was systematically conducted by quantitative evaluation of the effect of partitioning and adsorption, hydrogen bonding and hydrophilicity, and temperature on the retention of nucleosides and nucleobases. It was found that the retention was highly relevant on the partitioning, hydrogen bonding between solutes and PEG, and strong electrostatic interactions (attractive/repulsive) between solutes and silica. To further assess the separation performance, three kinds of polar compounds (nucleosides and nucleobases, organic acids and β-blockers) were chosen as probe compounds. Among the four PEG stationary phases, it was found that the higher PEG ligand density generally resulted into more superior separation performance to these polar compounds, that is, PEG200-bonded stationary phase with highest ligand density of 2.7 μmol m−2 generated better resolution. Furthermore, higher ligand bonding mass would increase the retention of nucleosides, nucleobases and organic acids except β-blockers. Generally, the HILIC stationary phase with continuous and dense hydrophilic layer is beneficial to the separation of polar analytes.
期刊介绍:
Separation sciences, in all their various forms such as chromatography, field-flow fractionation, and electrophoresis, provide some of the most powerful techniques in analytical chemistry and are applied within a number of important application areas, including archaeology, biotechnology, clinical, environmental, food, medical, petroleum, pharmaceutical, polymer and biopolymer research. Beyond serving analytical purposes, separation techniques are also used for preparative and process-scale applications. The scope and power of separation sciences is significantly extended by combination with spectroscopic detection methods (e.g., laser-based approaches, nuclear-magnetic resonance, Raman, chemiluminescence) and particularly, mass spectrometry, to create hyphenated techniques. In addition to exciting new developments in chromatography, such as ultra high-pressure systems, multidimensional separations, and high-temperature approaches, there have also been great advances in hybrid methods combining chromatography and electro-based separations, especially on the micro- and nanoscale. Integrated biological procedures (e.g., enzymatic, immunological, receptor-based assays) can also be part of the overall analytical process.