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Wang X, Cui J, Zhou J, Wang S, Gu Y, Liu X, Wang S. Preparation of polyacrylamide hydrophilic stationary phases with adjustable performance. J Chromatogr A 2023; 1702:464065. [PMID: 37224587 DOI: 10.1016/j.chroma.2023.464065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 05/09/2023] [Accepted: 05/10/2023] [Indexed: 05/26/2023]
Abstract
Polymer modified silica materials are widely used as stationary phases in hydrophilic interaction liquid chromatography (HILIC), whereas a stationary phase with excellent performance is highly desired. In this study, vinyl modified silica was first synthesized through a silane coupling reaction, and then a polyacrylamide modified silica (PAM-SIL) stationary phase was successfully prepared using acrylamide as a copolymer monomer via free radical polymerization. The retention behaviors of polar analytes on the stationary phase under various chromatographic conditions, including acetonitrile content, buffer concentration and pH values were investigated, and a typical hydrophilic interaction retention mechanism was inferred. Exceptionally, the separation performance of the stationary phases could be regulated by controlling the polymer structure. Model analytes separated rapidly on the stationary phase which has an optimal grafting amount of vinyl, with the highest number of theoretical plates of orotic acid reaching 119,966/m. While the stationary phases with high acrylamide concentrations exhibited enhanced retention behavior and higher resolution for analytes. The adjustable separation performance will have huge potential in future separation and analysis applications.
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Affiliation(s)
- Xiaoqing Wang
- University of Science and Technology of China, Hefei 230026, China; Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Jian Cui
- Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Jin Zhou
- Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Shuo Wang
- Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Yiming Gu
- Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Xiaowei Liu
- Advanced Membranes and Porous Materials Centre, Division of Physical Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Shudong Wang
- Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
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Shen Y, Geng H, Zhang F, Li Z, Yang B. A polyethyleneimine-functionalized polymer substrate polar stationary phase. J Chromatogr A 2023; 1689:463711. [PMID: 36586280 DOI: 10.1016/j.chroma.2022.463711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 12/01/2022] [Accepted: 12/09/2022] [Indexed: 12/14/2022]
Abstract
A polyethyleneimine (PEI)-functionalized polymer substrate polar stationary phase was prepared for hydrophilic interaction chromatography (HILIC) by grafting PEI onto poly(styrene-divinylbenzene) (PS-DVB) microspheres. The phase shows a U-shape retention profile and it exhibits typical hydrophilic characteristic when the organic solvent fraction in the mobile phase is > 60%. Hydrogen bonding, anion exchange, and hydrophobic interaction are involved in the retention mechanism. Good separation and unique selectivity for acidic, basic and neutral polar analytes were achieved. It showed extremely low column bleed (comparable to that of blank) under gradient elution mode (even to 50% fraction of water) and wide pH tollerance range (at least 1-13).
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Affiliation(s)
- Yufeng Shen
- Engineering Research Center of Pharmaceutical Process Chemistry, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East-China University of Science and Technology, 130 Meilong RD, Pharmacy School, Shanghai 200237, China
| | - Huiliang Geng
- Engineering Research Center of Pharmaceutical Process Chemistry, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East-China University of Science and Technology, 130 Meilong RD, Pharmacy School, Shanghai 200237, China
| | - Feifang Zhang
- Engineering Research Center of Pharmaceutical Process Chemistry, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East-China University of Science and Technology, 130 Meilong RD, Pharmacy School, Shanghai 200237, China.
| | - Zongying Li
- Engineering Research Center of Pharmaceutical Process Chemistry, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East-China University of Science and Technology, 130 Meilong RD, Pharmacy School, Shanghai 200237, China
| | - Bingcheng Yang
- Engineering Research Center of Pharmaceutical Process Chemistry, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East-China University of Science and Technology, 130 Meilong RD, Pharmacy School, Shanghai 200237, China.
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3
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Recent advances of innovative and high-efficiency stationary phases for chromatographic separations. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116647] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Bo C, Li Y, Liu B, Jia Z, Dai X, Gong B. Grafting copolymer brushes on polyhedral oligomeric silsesquioxanes silsesquioxane-decorated silica stationary phase for hydrophilic interaction liquid chromatography. J Chromatogr A 2021; 1659:462627. [PMID: 34700183 DOI: 10.1016/j.chroma.2021.462627] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/13/2021] [Accepted: 10/13/2021] [Indexed: 11/18/2022]
Abstract
A strategy is proposed to develop a stationary phase for hydrophilic interaction liquid chromatography (HILIC) using the synergistic effect of polyhedral oligomeric silsesquioxane (POSS) and copolymer brushes. Octahedral octa-aminopropylsisesquioxane (8NH2-POSS) was first bound to silica gel, followed by bromination to form a cubic initiator. Then, using acrylamide (AM) and dihydroxypropyl methacrylate (DPMA) as mixed monomers, surface initiated-atom transfer radical polymerization was conducted to prepare a stationary phase comprising cubic copolymer brushes with amide and diol groups. The characterization of the stationary phase confirmed the successful synthesis of Sil-NH2-POSS/Poly(AM-co-DPMA). The chromatographic properties were investigated using nucleosides, organic acids and β-agonists to find that our designed column has superior hydrophilic property, better separation performance compared with classical HILIC columns consisting of diol- or amino-modified silica. The systematic investigation of the retention mechanism and separation selectivity using various types of polar compounds revealed that Sil-NH2-POSS/Poly(AM-co-DPMA) follows a mixed-mode retention composed of HILIC and electrostatic interactions. Besides, it exhibits good column efficiency and stability. The role of 8NH2-POSS in the separation was evaluated by comparing the performance of Sil-NH2-POSS/Poly(AM-co-DPMA) and poly(AM-co-DPMA)-modified silica without 8NH2-POSS. In conclusion, our designed based on POSS and hydrophilic copolymer brushes can contribute to the development of HILIC separation materials with enhanced performance.
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Affiliation(s)
- Chunmiao Bo
- School of Chemistry and Chemical Engineering, North Minzu University, No. 204 Wenchang North Street, Xixia District, Yinchuan 750021, China; Ningxia Key Laboratory of Solar Chemical Conversion Technology, North Minzu University, Yinchuan, 750021,China; Key Laboratory for Chemical Engineering and Technology, State Ethnic Affairs Commission, North Minzu University, Yinchuan 750021, China.
| | - Yan Li
- School of Chemistry and Chemical Engineering, North Minzu University, No. 204 Wenchang North Street, Xixia District, Yinchuan 750021, China; Ningxia Key Laboratory of Solar Chemical Conversion Technology, North Minzu University, Yinchuan, 750021,China; Key Laboratory for Chemical Engineering and Technology, State Ethnic Affairs Commission, North Minzu University, Yinchuan 750021, China
| | - Bin Liu
- School of Chemistry and Chemical Engineering, North Minzu University, No. 204 Wenchang North Street, Xixia District, Yinchuan 750021, China; Ningxia Key Laboratory of Solar Chemical Conversion Technology, North Minzu University, Yinchuan, 750021,China; Key Laboratory for Chemical Engineering and Technology, State Ethnic Affairs Commission, North Minzu University, Yinchuan 750021, China
| | - Zhuanhong Jia
- College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, China
| | - Xiaojun Dai
- College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, China
| | - Bolin Gong
- School of Chemistry and Chemical Engineering, North Minzu University, No. 204 Wenchang North Street, Xixia District, Yinchuan 750021, China; Ningxia Key Laboratory of Solar Chemical Conversion Technology, North Minzu University, Yinchuan, 750021,China; Key Laboratory for Chemical Engineering and Technology, State Ethnic Affairs Commission, North Minzu University, Yinchuan 750021, China
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Hara T, Baron GV, Hata K, Izumi Y, Bamba T, Desmet G. Performance of functionalized monolithic silica capillary columns with different mesopore sizes using radical polymerization of octadecyl methacrylate. J Chromatogr A 2021; 1651:462282. [PMID: 34144397 DOI: 10.1016/j.chroma.2021.462282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 04/26/2021] [Accepted: 05/18/2021] [Indexed: 11/29/2022]
Abstract
We report on the possibility to enhance the phase ratio and retention factor in silica monoliths. According to pioneering work done by Núñez et al. [1], this enhancement is pursued by applying a stationary phase layer via radical polymerization with octadecyl methacrylate (ODM) as an alternative to the customary octadecylsilylation (C18-derivatization). The difference in band broadening, retention factor and separation selectivity between both approaches was compared. Different hydrothermal treatment temperatures for the column preparation were applied to produce monolithic silica structures with three different mesopore sizes (resp. 10, 13, and 16 nm, as determined by argon physisorption) while maintaining similar domain size (sum of through-pore and skeleton size). It has been found that the columns with the poly(octadecyl methacrylate)-phase (ODM columns) provided a 60 to 80% higher retention factor in methanol-water mixture compared to the octadecylsilylated (ODS) columns produced by starting from similar silica backbone structures. In acetonitrile-water mixture, the enhancement is smaller (15 to 30% times higher), yet significant. By adjusting the fabrication conditions (for both the preparation of the monolithic backbones and the surface functionalization), the achieved retention factors (up k = 4.89 for pentylbenzene in 80:20% (v/v) methanol/water) are obviously higher than obtained in the pioneering study on ODM monoliths of Núñez et al. [1], and column clogging could be completely avoided. In addition, also separation efficiencies were significantly higher than shown in Ref. [1], with plate heights as low as 5.8 μm. These plate heights are however inferior to those observed on the ODS-modified sister columns. The difference can be explained by the slower intra-skeleton diffusion displayed by the ODM-modified columns, in turn caused by the larger obstruction to diffusion originating from the thicker stationary phase layer.
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Affiliation(s)
- Takeshi Hara
- Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan; GL Sciences Inc., 237-2 Sayamagahara, Iruma, Saitama 358-0032, Japan
| | - Gino V Baron
- Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, Brussels B-1050, Belgium
| | - Kosuke Hata
- Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Yoshihiro Izumi
- Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Takeshi Bamba
- Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
| | - Gert Desmet
- Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, Brussels B-1050, Belgium.
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Comparison of the steric selectivity on hydrophilic interaction chromatography columns modified with poly(acrylamide) possessing different morphology. J Chromatogr A 2021; 1650:462207. [PMID: 34082188 DOI: 10.1016/j.chroma.2021.462207] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/23/2021] [Accepted: 04/25/2021] [Indexed: 11/24/2022]
Abstract
Poly(acrylamide) (PAAm)-modified hydrophilic interaction chromatography (HILIC) columns were prepared via surface-initiated atom transfer radical polymerization (SI-ATRP) and free radical polymerization (FRP) to generate brush-like and mushroom-like polymer chains on silica particles, respectively. The maltose homologues (MHs) and cyclodextrins (CDs) were chosen as analytes to evaluate steric selectivity by the different polymer morphologies in the ATRP-PAAm and the FRP-PAAm columns. The ATRP-PAAm exhibited superior retention than the FRP-PAAm and three commercial HILIC columns. The house-made PAAm columns provided significant hydrophilicity that enabled to analysis the oligosaccharides even in 60:40 mixture of acetonitrile-aqueous buffer. In the case of three ATRP-PAAm columns characterized by different polymer lengths and the density on the silica particles, those are different thickness of the water-enriched layer, and phase ratio φ, based on hydrophilicity of them columns. The logarithm of the retention factor (ln k) displayed a non-linear dependence on the inverse of the temperature (1/T, T = 278-333 K). Notably, a similar correlation was observed to exist between the logarithm of the phase ratio (ln φ), and 1/T. A van't Hoff plot was used to determine the thermodynamic parameters of the partition process for each MH. The values of the Gibbs free energy (ΔG°) for the analytes partition on the ATRP-PAAm columns were smaller than their counterparts measured for the FRP-PAAm columns; by contrast, the opposite trend was observed for the ΔG° values measured for CDs. The standard entropy ΔS° for MHs and CDs were comparable for the two types PAAm columns, while, the standard enthalpy, ΔH° displays significant difference between the ATRP and the FRP PAAm columns. These findings indicate that the differences between PAAm morphology and polymer densities on the stationary phase surface affect analyte differentiation on the basis of molecular steric factors. The higher selectivity for MHs and CDs displayed by ATRP-PAAm columns with respect to their FRP-PAAm and commercial amide columns will be useful for the fine separation of oligosaccharides.
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Ikegami T, Taniguchi A, Okada T, Horie K, Arase S, Ikegami Y. Functionalization using polymer or silane? A practical test method to characterize hydrophilic interaction chromatography phases in terms of their functionalization method. J Chromatogr A 2020; 1638:461850. [PMID: 33482613 DOI: 10.1016/j.chroma.2020.461850] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 12/21/2020] [Accepted: 12/23/2020] [Indexed: 12/28/2022]
Abstract
Herein, commercially available columns employed in hydrophilic interaction chromatography (HILIC) were characterized by determining their ability to selectively distinguish the minute structural differences between small molecules such as nucleosides and xanthines in complex sample matrices. Principal component analysis (PCA) was applied to the data obtained from structurally similar analytes, and the results showed that HILIC columns could generally be classified into two groups: (i) silane-modified columns that were prepared from either native silica particles or silica particles modified with low-molecular-weight silanes and (ii) polymer-modified columns obtained from silica particles functionalized with organic polymers. These two groups could be further subdivided based on the functionalities attached to the respective stationary phases. These results were confirmed via cluster analysis by preparing a dendrogram using the morphology-based selectivity parameters associated with the respective columns. We were able to determine the selectivity of columns for the OH groups, i.e., α(OH) and the prevailing pH conditions (cation- and anion-exchanging natures) on the surface of the respective stationary phases; α(theobromine/theophylline) was employed to obtain a similar two-dimensional plot. This test scheme, in which five compounds were analyze for each column, was helpful for understanding the impact of factors such as the hydrophilicity, degree of hydration, acidity/basicity, or the weak ion-exchange nature of the respective stationary phases on the separation characteristics of new HILIC stationary phases. The selectivity of columns for the CH2 group was also examined. The cation-exchange nature of the HILIC columns significantly influenced native silica columns and some polymer-modified columns. Herein, 45 commercially available HILIC columns were classified according to this method, and the results proved useful for understanding distinct separation characteristics of each HILIC column, enabling improved column selection.
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Affiliation(s)
- Tohru Ikegami
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan.
| | - Ashin Taniguchi
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan
| | - Tomoyuki Okada
- YMC Co., Ltd., Miwa, Miwa-cho, Fukuchiyama, Kyoto, 620-1445, Japan
| | - Kanta Horie
- Translational Science, Neurology Business Group, Eisai Co., Ltd. Tsukuba, Ibaraki, 300-2635, Japan; Department of Neurology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Syuntaro Arase
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan; Formulation Research, Pharmaceutical Science & Technology Core Function Unit, Medicine Development Center, Eisai Co., Ltd., Kagamigahara, Gifu, 501-6195, Japan
| | - Yuka Ikegami
- Okami Chemical Industry Co., Ltd., Makishima, Enba 78, Uji, Kyoto, 611-0041, Japan
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