1
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Long K, Guan J, Yu J, Zhang D, Shi S. Preparation and study of a capillary electrochromatographic column prepared by conjugating β-CD COFs and gold-poly glycidyl methacrylate nanoparticles. Mikrochim Acta 2024; 191:457. [PMID: 38980449 DOI: 10.1007/s00604-024-06533-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Accepted: 06/27/2024] [Indexed: 07/10/2024]
Abstract
A new enantioselective open-tubular capillary electrochromatography (OT-CEC) was developed employing β-cyclodextrin covalent organic frameworks (β-CD COFs) conjugated gold-poly glycidyl methacrylate nanoparticles (Au-PGMA NPs) as a stationary phase. The resulting coating layer on the inner wall of the fabricated capillary column was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), energy dispersive spectroscopy (EDS), and electroosmotic flow (EOF) experiments. The performance of the fabricated capillary column was evaluated by CEC using enantiomers of seven model analytes, including two proton pump inhibitors (PPIs, omeprazole and tenatoprazole), three amino acids (AAs, tyrosine, phenylalanine, and tryptophan), and two fluoroquinolones (FQs, gatifloxacin and sparfloxacin). The influences of coating time, buffer concentration, buffer pH, and applied voltage on enantioseparation were investigated to obtain satisfactory enantioselectivity. In the optimum conditions, the enantiomers of seven analytes were fully resolved within 10 min with high resolutions of 3.03 to 5.25. The inter- to intra-day and column-to-column repeatabilities of the fabricated capillary column were lower than 4.26% RSD. Furthermore, molecular docking studies were performed based on the chiral fabricated column and as ligand isomers of analytes using Auto Dock Tools. The binding energies and interactions acquired from docking results of analytes supported the experimental data.
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Affiliation(s)
- Ke Long
- School of Chemical Technology, Liaoning & Shenyang Key Laboratory of Functional Dye and Pigment, Shenyang University of Chemical Technology, Shenyang, P. R. China
| | - Jin Guan
- School of Chemical Technology, Liaoning & Shenyang Key Laboratory of Functional Dye and Pigment, Shenyang University of Chemical Technology, Shenyang, P. R. China.
| | - Jiatong Yu
- School of Chemical Technology, Liaoning & Shenyang Key Laboratory of Functional Dye and Pigment, Shenyang University of Chemical Technology, Shenyang, P. R. China
| | - Dongxiang Zhang
- School of Chemical Technology, Liaoning & Shenyang Key Laboratory of Functional Dye and Pigment, Shenyang University of Chemical Technology, Shenyang, P. R. China
| | - Shuang Shi
- School of Chemical Technology, Liaoning & Shenyang Key Laboratory of Functional Dye and Pigment, Shenyang University of Chemical Technology, Shenyang, P. R. China
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2
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Gavara R, Royuela S, Zamora F. A minireview on covalent organic frameworks as stationary phases in chromatography. Front Chem 2024; 12:1384025. [PMID: 38606080 PMCID: PMC11006975 DOI: 10.3389/fchem.2024.1384025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 03/15/2024] [Indexed: 04/13/2024] Open
Abstract
Advances in the design of novel porous materials open new avenues for the development of chromatographic solid stationary phases. Covalent organic frameworks (COFs) are promising candidates in this context due to their remarkable structural versatility and exceptional chemical and textural properties. In this minireview, we summarize the main strategies followed in recent years to apply these materials as stationary phases for chromatographic separations. We also comment on the perspectives of this new research field and potential directions to expand the applicability and implementation of COF stationary phases in analytical systems.
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Affiliation(s)
- Raquel Gavara
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
- Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, Madrid, Spain
| | - Sergio Royuela
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Félix Zamora
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, Spain
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3
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Ali N, Wang F, Qi L. Open tubular capillary electrochromatography with dual-responsive polymer as coating for separation of chromones. J Chromatogr A 2024; 1714:464595. [PMID: 38141483 DOI: 10.1016/j.chroma.2023.464595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/11/2023] [Accepted: 12/18/2023] [Indexed: 12/25/2023]
Abstract
Fabricating polymeric coatings that are responsive to multiple/dual stimuli is crucial and remains a major challenge in the development of highly efficient open tubular capillary electrochromatography (OT-CEC). In this study, a pH and temperature-responsive block copolymer, poly(styrene-maleic anhydride 2-dimethylamino ethyl methacrylate), P(St-MAn-DMAEMA), was designed and synthesized. Using P(St-MAn-DMAEMA) as the coating, an OT-CEC protocol was constructed for the analysis of chromones. The morphology and hydrophobicity-hydrophilicity of the polymeric coating could change via varying the environmental conditions, affecting the separation efficiency of OT-CEC. Interestingly, the best performance of OT-CEC was achieved at pH 9.7 and 45 °C via tuning the interactions between the coating and the analytes. Additionally, the proposed OT-CEC method exhibited a good linear range for the detection of the three test chromones from 10.0 to 100.0 μM, with all correlation coefficients (R2) >0.997. The coatings also had good stability and reusability. This work provides an approach for the preparation of new multiple-stimuli-responsive polymeric coatings for the establishment of OT-CEC systems.
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Affiliation(s)
- Nasir Ali
- Beijing National Laboratory of Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, No. 2 Zhongguancun Beiyijie, Beijing 100190, China; University of Chinese Academy of Sciences, 19A Yuquanlu, Beijing 100049, China
| | - Fuyi Wang
- Beijing National Laboratory of Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, No. 2 Zhongguancun Beiyijie, Beijing 100190, China; University of Chinese Academy of Sciences, 19A Yuquanlu, Beijing 100049, China
| | - Li Qi
- Beijing National Laboratory of Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, No. 2 Zhongguancun Beiyijie, Beijing 100190, China; University of Chinese Academy of Sciences, 19A Yuquanlu, Beijing 100049, China.
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4
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Mao Z, Chen J, Jiang D, Zhao N, Qin Y, Mao X, Fang F, Ma P. Itaconic Acid-Based Organic-Polymer Monolithic Column for Hydrophilic Capillary Electrochromatography and Its Application in Pharmaceutical Analysis. ACS OMEGA 2024; 9:1554-1561. [PMID: 38222631 PMCID: PMC10785275 DOI: 10.1021/acsomega.3c08031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/07/2023] [Accepted: 12/11/2023] [Indexed: 01/16/2024]
Abstract
Itaconic acid is an excellent hydrophilic monomer owing to the dicarboxylic group possessing strong polarity. This study reports on the preparation of a new organic-polymer monolithic column poly(itaconic acid-co-3-(acryloyloxy)-2-hydroxypropyl methacrylate) (poly(IA-co-AHM)) featuring excellent hydrophilic chromatography ability and its application in pharmaceutical analysis. The monolithic column was successfully synthesized by using the monomer itaconic acid and the cross-linker AHM through an in situ copolymerization method. Optical microscopy, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) were employed for the characterization of the poly(IA-co-AHM) monolithic column, and all of these demonstrated that the prepared itaconic acid-based monolithic column exhibited satisfactory permeability and a homogeneous porous structure. Owing to the carboxylic groups of itaconic acid, a cathodic electroosmotic flow (EOF) was generated on the itaconic acid-based monolithic column among the pH ranges of the mobile phase from 4.0 to 9.0. Depending on the powerful hydrophilic interactions, different kinds of polar substances, including thioureas, nucleoside drugs, sulfonamides, and polypeptides, were separated efficiently by the itaconic acid-based monoliths poly(IA-co-AHM). The separations of polar compounds were successfully realized, even at a lower level of 50% acetonitrile content on this monolithic column. The highest column efficiencies corresponding to N,N'-dimethylthiourea and idoxuridine were 102 720 and 124 267 N/m, respectively. The poly(IA-co-AHM) monolithic column displayed excellent repeatability, whose relative standard deviations (RSDs) of the retention time and peak area were both lower than 5.0%. All experimental results demonstrated that the new itaconic acid-functionalized monolithic column was greatly appropriate to separate the polar compounds under the HILIC mode.
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Affiliation(s)
- Zhenkun Mao
- Department
of Pharmacy, Henan Provincial People’s
Hospital, Zhengzhou 450003, Henan, China
- Department
of Pharmacy, People’s Hospital of
Zhengzhou University, Zhengzhou University, Zhengzhou 450003, Henan, China
| | - Jinxiu Chen
- Department
of Pharmacy, Henan Provincial People’s
Hospital, Zhengzhou 450003, Henan, China
- Department
of Pharmacy, People’s Hospital of
Zhengzhou University, Zhengzhou University, Zhengzhou 450003, Henan, China
| | - Dandan Jiang
- Department
of Pharmacy, Henan Provincial People’s
Hospital, Zhengzhou 450003, Henan, China
- Department
of Pharmacy, People’s Hospital of
Zhengzhou University, Zhengzhou University, Zhengzhou 450003, Henan, China
| | - Ningmin Zhao
- Department
of Pharmacy, Henan Provincial People’s
Hospital, Zhengzhou 450003, Henan, China
- Department
of Pharmacy, People’s Hospital of
Zhengzhou University, Zhengzhou University, Zhengzhou 450003, Henan, China
| | - Yinhui Qin
- Department
of Pharmacy, Henan Provincial People’s
Hospital, Zhengzhou 450003, Henan, China
- Department
of Pharmacy, People’s Hospital of
Zhengzhou University, Zhengzhou University, Zhengzhou 450003, Henan, China
| | - Xiangju Mao
- Zhengzhou
Institute of Multipurpose Utilization of Mineral Resources, CAGS, Zhengzhou 450006, China
| | - Fengqin Fang
- Department
of Pharmacy, Henan Provincial People’s
Hospital, Zhengzhou 450003, Henan, China
- Department
of Pharmacy, People’s Hospital of
Zhengzhou University, Zhengzhou University, Zhengzhou 450003, Henan, China
| | - Peizhi Ma
- Department
of Pharmacy, Henan Provincial People’s
Hospital, Zhengzhou 450003, Henan, China
- Department
of Pharmacy, People’s Hospital of
Zhengzhou University, Zhengzhou University, Zhengzhou 450003, Henan, China
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5
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Li Q, Sun W, Li Z, Chen Z. Fluorinated covalent-organic polymers as stationary phase for analysis of organic fluorides by open-tubular capillary electrochromatography. J Sep Sci 2023; 46:e2300138. [PMID: 37269198 DOI: 10.1002/jssc.202300138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 05/19/2023] [Accepted: 05/22/2023] [Indexed: 06/04/2023]
Abstract
Fluorinated porous materials, which can provide specific fluorine-fluorine interaction, hold great promise for fluoride analysis. Here, a novel fluorinated covalent-organic polymer was prepared by using 2,4,6-tris(4-aminophenyl)-1,3,5-triazine and 2,3,5,6-tetrafluorotelephtal aldehyde as the precursors and introduced as stationary phase for open-tubular capillary electrochromatography. The as-synthesized fluorinated covalent-organic polymer and the modified capillary column were characterized by infrared spectroscopy, scanning electron microscopy, and energy dispersive X-ray spectrometry. Based on strong hydrophobic interaction and fluorine-fluorine interaction provided by fluorinated covalent-organic polymer coating layer, the modified column showed powerful separation selectivity toward hydrophobic compounds, organic fluorides, and fluorinated pesticides. Additionally, the fluorinated covalent-organic polymer with good porosity and regular shape was uniformly and tightly coated on the capillary inner wall. The obtained highest column efficiency could reach up to 1.2 × 105 plates⋅m-1 for fluorophenol. The loading capacity of the modified column can reach 141 pmol for trifluorotoluene. Besides, the relative standard deviations of retention times for intraday run (n = 5), interday run (n = 3), and between columns (n = 3) were all less than 2.55%. Significantly, this novel fluorinated material-based stationary phase shows great application potential in fluorides analysis.
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Affiliation(s)
- Qiaoyan Li
- School of Pharmaceutical Sciences, Wuhan University, Wuhan, P. R. China
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan, P. R. China
| | - Wenqi Sun
- School of Pharmaceutical Sciences, Wuhan University, Wuhan, P. R. China
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan, P. R. China
| | - Zhentao Li
- School of Pharmaceutical Sciences, Wuhan University, Wuhan, P. R. China
| | - Zilin Chen
- School of Pharmaceutical Sciences, Wuhan University, Wuhan, P. R. China
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan, P. R. China
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6
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Ahmed MA, Yu RB, Quirino JP. Recent developments in open tubular liquid chromatography and electrochromatography from 2019–2021. Trends Analyt Chem 2023. [DOI: 10.1016/j.trac.2023.117045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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7
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Capillary electrophoresis in phytochemical analysis: Advances and applications in the period 2018–2021. Trends Analyt Chem 2023. [DOI: 10.1016/j.trac.2023.116974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
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8
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Recent applications and chiral separation developments based on stationary phases in open tubular capillary electrochromatography (2019–2022). J Pharm Anal 2023; 13:323-339. [PMID: 37181297 PMCID: PMC10173184 DOI: 10.1016/j.jpha.2023.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 01/16/2023] [Accepted: 01/31/2023] [Indexed: 02/08/2023] Open
Abstract
Capillary electrochromatography (CEC) plays a significant role in chiral separation via the double separation principle, partition coefficient difference between the two phases, and electroosmotic flow-driven separation. Given the distinct properties of the inner wall stationary phase (SP), the separation ability of each SP differs from one another. Particularly, it provides large room for promising applications of open tubular capillary electrochromatography (OT-CEC). We divided the OT-CEC SPs developed over the past four years into six types: ionic liquids, nanoparticle materials, microporous materials, biomaterials, non-nanopolymers, and others, to mainly introduce their characteristics in chiral drug separation. There also added a few classic SPs that occurred within ten years as supplements to enrich the features of each SP. Additionally, we discuss their applications in metabolomics, food, cosmetics, environment, and biology as analytes in addition to chiral drugs. OT-CEC plays an increasingly significant role in chiral separation and may promote the development of capillary electrophoresis (CE) combined with other instruments in recent years, such as CE with mass spectrometry (CE/MS) and CE with ultraviolet light detector (CE/UV).
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9
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Hu W, Zhou W, Wang C, Liu Z, Chen Z. Direct coupling in-tube solid-phase microextraction with mass spectrometry using polymer coated open-tubular column for rapid analysis of antiepileptic drugs in biofluids. Anal Chim Acta 2023; 1240:340775. [PMID: 36641145 DOI: 10.1016/j.aca.2022.340775] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 12/25/2022] [Accepted: 12/30/2022] [Indexed: 12/31/2022]
Abstract
Development of high-throughput and rapid screening analytical method is in high demand for anti-doping and clinical point-of-care (POC) analysis. Solid-phase microextraction and mass spectrometry direct coupling (SPME-MS) has been proved as a rapid and effective way for target analysis in complex sample matrixes. An online direct coupling of in-tube SPME (IT-SPME) with MS using polymer coated open-tubular column has been developed in this work. A sharp stainless-steel needle was attached at the end of the SPME column, which enables the direct ionization of the analytes after elution from the IT-SPME column. Itaconic acid-benzene co-polymer was in-situ grown on the inner surface of the fused silica capillary and used as extraction phase. This column has low backpressure and provides both hydrophobic and weak cationic exchange interaction with the target analytes due to the chemical properties. The developed online IT-SPME-MS method showed good extraction performance towards various target analytes and good reusability at least for 60 times. As a proof-of-concept application, the above method was applied for the analysis of antiepileptic drugs (AEDs) in both plasma and urine samples with linear range (1 ng/mL-200 ng/mL), good linearity (R2 ≥ 0.99), and good reproducibility (intra-day RSDs less than 4.36%, inter-day RSDs less than 6.55%). The method exhibited high enrichment factors between 187 and 204 for the two AEDs and high sensitivity for the analysis of human plasma samples and urine samples.
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Affiliation(s)
- Wei Hu
- Department of Orthopedics Trauma and Microsurgery, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430072, China; Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan, 430071, China
| | - Wei Zhou
- Department of Orthopedics Trauma and Microsurgery, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430072, China
| | - Chenlu Wang
- Department of Orthopedics Trauma and Microsurgery, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430072, China
| | - Zichun Liu
- Department of Orthopedics Trauma and Microsurgery, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430072, China
| | - Zilin Chen
- Department of Orthopedics Trauma and Microsurgery, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430072, China; Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan, 430071, China.
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10
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Hu C, Li Z, Hu Z, Li Q, Fu Y, Chen Z. Synthesis of multifunctional crown ether covalent organic nanospheres as stationary phase for capillary electrochromatography. J Chromatogr A 2022; 1677:463323. [PMID: 35853421 DOI: 10.1016/j.chroma.2022.463323] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 07/04/2022] [Accepted: 07/08/2022] [Indexed: 01/14/2023]
Abstract
Crown ethers are macrocyclic polyether compounds containing multiple -oxo-methylene-structural units, which are often used for recognition of metal ions and ammonium ions. Inspired by the molecular design of rotaxanes, a novel covalent organic nanospheres material (CON ADBC-Tp) constructed by 4,4'-diaminodibenzo-18-crown-6 (ADBC) and 2,4,6-triformylphloroglucinol (Tp) was rationally designed as stationary phase for the separation of compounds containing imidazole structure. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) were carried out to confirm the morphology and composition of ADBC-Tp and ADBC-Tp modified capillary column. Thanks to the introduction of crown ether building ligands, the prepared capillary column exhibited excellent separation selectivity towards protonated imidazole structure, with benzimidazole and its 2-substituted derivatives as modal analytes. Moreover, separation of fungicides, nucleobases, short peptides and sulfanilamides were achieved on ADBC-Tp@capillary. The multifunctional ADBC-Tp@capillary with satisfactory reproducibility and stability gives great promise for separation science.
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Affiliation(s)
- Changjun Hu
- Department of Orthopedics Trauma and Microsurgery, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430072, China; Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan 430071, China
| | - Zhentao Li
- Department of Orthopedics Trauma and Microsurgery, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430072, China; Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan 430071, China
| | - Zhuang Hu
- Department of Orthopedics Trauma and Microsurgery, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430072, China; Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan 430071, China
| | - Qiaoyan Li
- Department of Orthopedics Trauma and Microsurgery, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430072, China; Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan 430071, China
| | - Yuanyuan Fu
- Department of Orthopedics Trauma and Microsurgery, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430072, China; Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan 430071, China
| | - Zilin Chen
- Department of Orthopedics Trauma and Microsurgery, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430072, China; Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan 430071, China.
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11
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Gu L, Guan J, Huang Z, Huo H, Shi S, Zhang D, Yan F. β-Cyclodextrin covalent organic framework supported by polydopamine as stationary phases for electrochromatographic enantioseparation. Electrophoresis 2022; 43:1446-1454. [PMID: 35353923 DOI: 10.1002/elps.202200029] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 03/24/2022] [Accepted: 03/26/2022] [Indexed: 02/01/2023]
Abstract
In this work, a new open-tubular capillary electrochromatography (OT-CEC) column was prepared using β-cyclodextrin covalent organic framework (β-CD COF) as a stationary phase. Polydopamine was used to assist fabrication of β-CD COF on an inner wall of a fused-silica capillary. The coating layer on the capillary was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Electroosmotic flow (EOF) was also studied to evaluate the variation of the inner wall of immobilized columns. Furthermore, the chiral separation effectiveness of the fabricated capillary column was evaluated by CEC using enantiomers of several related proton pump inhibitors as model analytes, including omeprazole, lansoprazole, pantoprazole and tenatoprazole. The effects of bonding time and concentration of β-CD COF, the type, concentration and pH of buffer, applied voltage were investigated to obtain satisfactory enantioselectivity. In the optimum conditions, the enantiomers of four analytes were resolved within 15 min with resolutions of 1.63-2.62. The relative standard deviation values for migration times and resolutions of the analytes representing intraday and interday were less than 6.75% and 4.24%, respectively. The results reveal that β-CD COF has great potential as chiral-stationary phases for enantioseparation in CEC.
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Affiliation(s)
- Lei Gu
- College of Chemical Engineering, Liaoning & Shenyang Key Laboratory of Functional Dye and Pigment, Shenyang University of Chemical Technology, Shenyang, P. R. China
| | - Jin Guan
- College of Chemical Engineering, Liaoning & Shenyang Key Laboratory of Functional Dye and Pigment, Shenyang University of Chemical Technology, Shenyang, P. R. China
| | - Ziwei Huang
- College of Chemical Engineering, Liaoning & Shenyang Key Laboratory of Functional Dye and Pigment, Shenyang University of Chemical Technology, Shenyang, P. R. China
| | - Hongyi Huo
- College of Chemical Engineering, Liaoning & Shenyang Key Laboratory of Functional Dye and Pigment, Shenyang University of Chemical Technology, Shenyang, P. R. China
| | - Shuang Shi
- College of Chemical Engineering, Liaoning & Shenyang Key Laboratory of Functional Dye and Pigment, Shenyang University of Chemical Technology, Shenyang, P. R. China
| | - Dongxiang Zhang
- College of Chemical Engineering, Liaoning & Shenyang Key Laboratory of Functional Dye and Pigment, Shenyang University of Chemical Technology, Shenyang, P. R. China
| | - Feng Yan
- College of Science, Shenyang University of Chemical Technology, Shenyang, P. R. China
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12
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Application of Sol–Gels Modified with Natural Plants Extracts as Stationary Phases in Open-Tubular Capillary Electrochromatography. Gels 2022; 8:gels8040198. [PMID: 35448099 PMCID: PMC9029637 DOI: 10.3390/gels8040198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 03/16/2022] [Accepted: 03/21/2022] [Indexed: 11/17/2022] Open
Abstract
Ethanol extracts of three widely growing plants were added to silica sol–gel solutions, which were subsequently applied as wall surface modifiers in inner quartz capillaries. Modified capillaries were used for open-tubular capillary electrochromatographic separation of nucleotides and amino groups containing biological compounds (neurotransmitters, amino acids and oligopeptides). The experiments were performed at physiological pH 7.40, and eventual changes of effective mobilities were calculated. Specific compounds characteristic for each plant were tested as sol–gel additives as well, and thus-modified capillaries were used for the separations of the same analytes under identical conditions. The aim of this study was to find out possible interactions between physiological compounds and extracts of freely available plants anchorded in the sol-gel stationary phase in the flowing system. Even though the amount of the modifier in each capillary is very small, basic statistical evaluation showed some not negligible changes in effective mobility of tested analytes. These changes were bigger than ±5% for separations of nucleotides in capillaries with curcuma, Moringa or the mixture of synthetic additives as the sol-gel aditive, and for separations of amino compounds where these changes varying by additive, analyte by analyte.
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13
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Qi L, Qiao J. Advances in stimuli-responsive polymeric coatings for open-tubular capillary electrochromatography. J Chromatogr A 2022; 1670:462957. [DOI: 10.1016/j.chroma.2022.462957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 02/27/2022] [Accepted: 03/09/2022] [Indexed: 10/18/2022]
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14
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Practical Evaluation of Chitosan-Based Chiral Stationary Phase for Pharmaceutical Analysis by High-Performance Liquid Chromatography. Chromatographia 2022. [DOI: 10.1007/s10337-022-04128-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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15
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Štěpánová S, Kašička V. Applications of capillary electromigration methods for separation and analysis of proteins (2017–mid 2021) – A review. Anal Chim Acta 2022; 1209:339447. [DOI: 10.1016/j.aca.2022.339447] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 01/04/2022] [Accepted: 01/04/2022] [Indexed: 12/11/2022]
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16
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Lei X, Zhang B, Zhang Y, Huang T, Tang F, Wu X. In situ photoinitiated fabrication of phosphorylcholine-functionalized polyhedral oligomeric silsesquioxane hybrid monolithic column for mixed-mode capillary electrochromatography. Analyst 2022; 147:2253-2263. [DOI: 10.1039/d2an00195k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A phosphorylcholine-functionalized POSS hybrid monolithic column was synthesized via UV curing. It exhibits hydrophilic interaction and weak cation exchange chromatography retention mechanism for the separation of typical polar and charged compounds.
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Affiliation(s)
- Xiaoyun Lei
- Key Laboratory for Analytical Science of Food Safety and Biology; College of Chemistry, Fuzhou University, Fuzhou 350116, China
| | - Bingyu Zhang
- Key Laboratory for Analytical Science of Food Safety and Biology; College of Chemistry, Fuzhou University, Fuzhou 350116, China
| | - Yi Zhang
- Key Laboratory for Analytical Science of Food Safety and Biology; College of Chemistry, Fuzhou University, Fuzhou 350116, China
| | - Ting Huang
- Key Laboratory for Analytical Science of Food Safety and Biology; College of Chemistry, Fuzhou University, Fuzhou 350116, China
| | - Fengxiang Tang
- Key Laboratory for Analytical Science of Food Safety and Biology; College of Chemistry, Fuzhou University, Fuzhou 350116, China
| | - Xiaoping Wu
- Key Laboratory for Analytical Science of Food Safety and Biology; College of Chemistry, Fuzhou University, Fuzhou 350116, China
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17
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Kašička V. Recent developments in capillary and microchip electroseparations of peptides (2019-mid 2021). Electrophoresis 2021; 43:82-108. [PMID: 34632606 DOI: 10.1002/elps.202100243] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/29/2021] [Accepted: 09/30/2021] [Indexed: 12/19/2022]
Abstract
The review provides a comprehensive overview of developments and applications of high performance capillary and microchip electroseparation methods (zone electrophoresis, isotachophoresis, isoelectric focusing, affinity electrophoresis, electrokinetic chromatography, and electrochromatography) for analysis, microscale isolation, and physicochemical characterization of peptides from 2019 up to approximately the middle of 2021. Advances in the investigation of electromigration properties of peptides and in the methodology of their analysis, such as sample preparation, sorption suppression, EOF control, and detection, are presented. New developments in the individual CE and CEC methods are demonstrated and several types of their applications are shown. They include qualitative and quantitative analysis, determination in complex biomatrices, monitoring of chemical and enzymatic reactions and physicochemical changes, amino acid, sequence, and chiral analyses, and peptide mapping of proteins. In addition, micropreparative separations and determination of significant physicochemical parameters of peptides by CE and CEC methods are described.
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Affiliation(s)
- Václav Kašička
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Prague 6, Czechia
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18
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Zhou W, Yu X, Liu Y, Sun W, Chen Z. Porous layer open-tubular column with styrene and itaconic acid-copolymerized polymer as stationary phase for capillary electrochromatography-mass spectrometry. Electrophoresis 2021; 42:2664-2671. [PMID: 34499755 DOI: 10.1002/elps.202100148] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 09/01/2021] [Accepted: 09/06/2021] [Indexed: 11/11/2022]
Abstract
Enhancing the specific surface area of stationary phase is important in chromatographic science, especially in open-tubular column in which the coating only exists on the inner surface. In this work, a porous layer open-tubular (PLOT) column with stationary phase of styrene and itaconic acid-copolymerized polymer was developed. Thermal-initiated polymerization method with strategies like controlling the ratio of reaction reagents to solvents and reaction time, confinement by the narrow inner diameter of capillary were used for preparing the stationary phase with uniform structure and relatively thick layer. Due to the high separation efficiency and capacity, the PLOT column was used for capillary electrochromatography (CEC) separation of multiple groups of analytes like alkylbenzenes, phenyl amines, phenols, vanillins, and sulfonamides with theoretical plates (N) up to 1,54,845 N/m. In addition, due to high permeability of the CEC column and large electroosmotic flow mobility generated by abundant carboxyl groups in the coating material, the PLOT-CEC column was successfully coupled with mass spectrometry (MS) through a sheath flow interface. The developed PLOT-CEC-MS method was used for the analysis of antiseptics like parabens and herbicides like pyridines.
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Affiliation(s)
- Wei Zhou
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministryof Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan University School of Pharmaceutical Sciences, Wuhan, P. R. China.,State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing, P. R. China
| | - Xinhong Yu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministryof Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan University School of Pharmaceutical Sciences, Wuhan, P. R. China.,State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing, P. R. China
| | - Yikun Liu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministryof Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan University School of Pharmaceutical Sciences, Wuhan, P. R. China
| | - Wenqi Sun
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministryof Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan University School of Pharmaceutical Sciences, Wuhan, P. R. China
| | - Zilin Chen
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministryof Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan University School of Pharmaceutical Sciences, Wuhan, P. R. China.,State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing, P. R. China
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19
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Sun W, Liu Y, Zhou W, Li Z, Chen Z. In-situ growth of a spherical vinyl-functionalized covalent organic framework as stationary phase for capillary electrochromatography-mass spectrometry analysis. Talanta 2021; 230:122330. [PMID: 33934787 DOI: 10.1016/j.talanta.2021.122330] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 03/16/2021] [Accepted: 03/18/2021] [Indexed: 11/29/2022]
Abstract
Column technology is an important part in capillary electrochromatographic science. Developing novel stationary phase with high separation efficiency and high loading capacity is an essential work. In this work, a novel spherical vinyl-functionalized covalent-organic framework (COF-V) was synthesized at room temperature and firstly employed as stationary phase for CEC-MS analysis. The COF-V based CEC column was characterized by scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. The results proved the successful modification of COF-V. The COF-V based column possesses the advantages like strong electroosmotic flow, high separation efficiency and high loading capacity. The CEC column showed powerful separation selectivity to several kinds of compounds, and the highest column efficiency (theoretical plates, N) was over 1.4 × 105 plates·m-1 for methylbenzene. Besides, the COF-V modified column exhibited excellent repeatability and stability. The relative standard deviations (RSDs) of retention times for intra-day (n = 5), inter-day (n = 3) runs and column-to-column (n = 3) were all less than 2.1%. Hence, the COF-V modified column was successfully applied in CEC-MS for determination of antiepileptic drug, triazine herbicides and active ingredients in traditional Chinese medicine.
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Affiliation(s)
- Wenqi Sun
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China; State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing, 100080, China
| | - Yikun Liu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China; State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing, 100080, China
| | - Wei Zhou
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China
| | - Zhentao Li
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China
| | - Zilin Chen
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China; State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing, 100080, China.
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20
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Preparation and evaluation of chiral open-tubular columns supported with zeolite silica nanoparticles and single/dual chiral selectors using capillary electrochromatography with amperometric detection. J Chromatogr A 2021; 1651:462298. [PMID: 34111678 DOI: 10.1016/j.chroma.2021.462298] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/21/2021] [Accepted: 05/23/2021] [Indexed: 11/22/2022]
Abstract
In this work, novel stationary phase coatings by zeolite SiO2NPs coupled with β-cyclodextrin (β-CD) or β-CD/L-phenylalanine were developed for chiral open-tubular capillary electrochromatography (OT-CEC). The OT columns were prepared taking advantage of the strong adhesion of polydopamine in one-step method. Scanning electron micrography and electroosmotic flow were used to characterize the prepared single/dual-selector OT columns. Chiral separation of four chiral analytes (catechin/epicatechin, ephedrine/pseudoephedrine, ritodrine and salbutamol) was carried out in order to evaluate the performance of the prepared columns in OT-CEC with amperometric detection system. In terms of migration time, peak area, resolution, and selectivity factor of catechin/epicatechin and salbutamol, the run-to-run, day-to-day, and column-to-column repeatability were within 8.9%. Under the optimum conditions, the developed methods were applied for the analyses of Chinese herbal medicine Catechu herbs and salbutamol aerosol samples.
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21
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El Deeb S, Silva CF, Junior CSN, Hanafi RS, Borges KB. Chiral Capillary Electrokinetic Chromatography: Principle and Applications, Detection and Identification, Design of Experiment, and Exploration of Chiral Recognition Using Molecular Modeling. Molecules 2021; 26:2841. [PMID: 34064769 PMCID: PMC8151978 DOI: 10.3390/molecules26102841] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/04/2021] [Accepted: 05/07/2021] [Indexed: 12/19/2022] Open
Abstract
This work reviews the literature of chiral capillary electrokinetic chromatography from January 2016 to March 2021. This is done to explore the state-of-the-art approach and recent developments carried out in this field. The separation principle of the technique is described and supported with simple graphical illustrations, showing migration under normal and reversed polarity modes of the separation voltage. The most relevant applications of the technique for enantioseparation of drugs and other enantiomeric molecules in different fields using chiral selectors in single, dual, or multiple systems are highlighted. Measures to improve the detection sensitivity of chiral capillary electrokinetic chromatography with UV detector are discussed, and the alternative aspects are explored, besides special emphases to hyphenation compatibility to mass spectrometry. Partial filling and counter migration techniques are described. Indirect identification of the separated enantiomers and the determination of enantiomeric migration order are mentioned. The application of Quality by Design principles to facilitate method development, optimization, and validation is presented. The elucidation and explanation of chiral recognition in molecular bases are discussed with special focus on the role of molecular modeling.
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Affiliation(s)
- Sami El Deeb
- Institute of Medicinal and Pharmaceutical Chemistry, Technische Universität Braunschweig, 38106 Braunschweig, Germany
| | - Camilla Fonseca Silva
- Departamento de Ciências Naturais, Campus Dom Bosco, Universidade Federal de São João del-Rei (UFSJ), Praça Dom Helvécio 74, Fábricas, São João del-Rei 36301-160, Minas Gerais, Brazil; (C.F.S.); (C.S.N.J.); (K.B.B.)
| | - Clebio Soares Nascimento Junior
- Departamento de Ciências Naturais, Campus Dom Bosco, Universidade Federal de São João del-Rei (UFSJ), Praça Dom Helvécio 74, Fábricas, São João del-Rei 36301-160, Minas Gerais, Brazil; (C.F.S.); (C.S.N.J.); (K.B.B.)
| | - Rasha Sayed Hanafi
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy and Biotechnology, German University in Cairo, Cairo 11835, Egypt;
| | - Keyller Bastos Borges
- Departamento de Ciências Naturais, Campus Dom Bosco, Universidade Federal de São João del-Rei (UFSJ), Praça Dom Helvécio 74, Fábricas, São João del-Rei 36301-160, Minas Gerais, Brazil; (C.F.S.); (C.S.N.J.); (K.B.B.)
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22
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Przybylska A, Gackowski M, Koba M. Application of Capillary Electrophoresis to the Analysis of Bioactive Compounds in Herbal Raw Materials. Molecules 2021; 26:2135. [PMID: 33917716 PMCID: PMC8068163 DOI: 10.3390/molecules26082135] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/04/2021] [Accepted: 04/06/2021] [Indexed: 12/17/2022] Open
Abstract
The article is a summary of scientific reports from the last 16 years (2005-2021) on the use of capillary electrophoresis to analyze polyphenolic compounds, coumarins, amino acids, and alkaloids in teas or different parts of plants used to prepare aqueous infusions, commonly known as "tea" or decoctions. This literature review is based on PRISMA guidelines and articles selected in base of criteria carried out using PICOS (Population, Intervention, Comparison, Outcome, Study type). The analysis showed that over 60% of articles included in this manuscript comes from China. The literature review shows that for the selective electrophoretic separation of polyphenolic and flavonoid compounds, the most frequently used capillary electromigration technique is capillary electrophoresis with ultraviolet detection. Nevertheless, the use of capillary electrophoresis-mass spectrometry allows for the sensitive determination of analytes with a lower limit of detection and gives hope for routine use in the analysis of functional foods. Moreover, using the modifications in electrochemical techniques allows methods sensitivity reduction along with the reduction of analysis time.
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Affiliation(s)
- Anna Przybylska
- Department of Toxicology and Bromatology, Faculty of Pharmacy, L. Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Torun, A. Jurasza 2 Street, PL-85089 Bydgoszcz, Poland; (M.G.); (M.K.)
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23
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Ali A, Sun G, Kim JS, Kim YS, An HJ, Cheong WJ. Preparation and Evaluation of 2 m Long Open Tubular Capillary Columns of 50 μm Internal Diameter for Separation of Peptides in Liquid Chromatography. Chromatographia 2021. [DOI: 10.1007/s10337-020-04003-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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24
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Caslavska J, Thormann W. Bioanalysis of drugs and their metabolites by chiral electromigration techniques (2010-2020). Electrophoresis 2021; 42:1744-1760. [PMID: 33570170 DOI: 10.1002/elps.202000383] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 02/03/2021] [Accepted: 02/04/2021] [Indexed: 12/11/2022]
Abstract
The further development and application of capillary electromigration techniques for the enantioselective determination of drugs and their metabolites in body fluids, tissues, and in vitro preparations during the 2010 to 2020 time period continued to proof their usefulness and attractiveness in bioanalysis. This review discusses the principles and important aspects of capillary electrophoresis- based chiral drug bioassays, provides a survey of the assays reported during the past 10 years and presents an overview of the key achievements encountered in that time period. For systems with charged chiral selectors, special attention is paid on assays that feature field-amplified sample injection to enable the determination of ppb levels of analytes and optimized online incubation procedures for the rapid assessment of a metabolic pathway. Applications discussed encompass the pharmacokinetics of drug enantiomers in vivo and in vitro, the impact of inhibitors on metabolic steps, the elucidation of the stereoselectivity of drug metabolism in vivo and in vitro, and drug enantiomers in toxicological, forensic, and doping analysis.
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Affiliation(s)
- Jitka Caslavska
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Wolfgang Thormann
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
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25
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Krait S, Konjaria ML, Scriba GKE. Advances of capillary electrophoresis enantioseparations in pharmaceutical analysis (2017-2020). Electrophoresis 2021; 42:1709-1725. [PMID: 33433919 DOI: 10.1002/elps.202000359] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 01/04/2021] [Accepted: 01/04/2021] [Indexed: 02/06/2023]
Abstract
Capillary electrophoresis is a powerful technique for the analysis of polar chiral compounds and has been widely accepted for analytical enantioseparations of drug compounds in pharmaceuticals and biological media. In addition, many mechanistic studies have been conducted in an attempt to rationalize enantioseparations in combination with spectroscopic and computational techniques. The present review will focus on recent examples of mechanistic aspects and summarize recent applications of stereoselective pharmaceutical and biomedical analysis published between January 2017 and November 2020. Various separation modes including electrokinetic chromatography in combination with several detection modes including laser-induced fluorescence, mass spectrometry and contactless conductivity detection will be discussed. A general trend also observed in other analytical techniques is the application of quality by design principles in method development and optimization.
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Affiliation(s)
- Sulaiman Krait
- Department of Pharmaceutical/Medicinal Chemistry, Philosophenweg 14, Friedrich Schiller University, Jena, Germany
| | - Mari-Luiza Konjaria
- Department of Pharmaceutical/Medicinal Chemistry, Philosophenweg 14, Friedrich Schiller University, Jena, Germany
| | - Gerhard K E Scriba
- Department of Pharmaceutical/Medicinal Chemistry, Philosophenweg 14, Friedrich Schiller University, Jena, Germany
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26
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27
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Maistrenko VN, Zil’berg RA. Enantioselective Voltammetric Sensors on the Basis of Chiral Materials. JOURNAL OF ANALYTICAL CHEMISTRY 2020. [DOI: 10.1134/s1061934820120102] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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28
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Kartsova LA, Makeeva DV, Bessonova EA. Current Status of Capillary Electrophoresis. JOURNAL OF ANALYTICAL CHEMISTRY 2020. [DOI: 10.1134/s1061934820120084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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29
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Mao Z, Li Z, Hu C, Liu Y, Li Q, Chen Z. Glycine-modified organic polymer monolith featuring zwitterionic functionalities for hydrophilic capillary electrochromatography. J Chromatogr A 2020; 1629:461497. [PMID: 32858454 DOI: 10.1016/j.chroma.2020.461497] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 08/14/2020] [Accepted: 08/18/2020] [Indexed: 01/01/2023]
Abstract
Allylglycine, a conventional amino acid derivative, possesses typical zwitterionic and hydrophilic functionalities deriving from the carboxyl and amino groups in its structure. A novel monolithic column poly(allylglycine-co-1, 3, 5-triacryloylhexahydro-1, 3, 5-triazine) (AGly-co-TAT) with powerful hydrophilic selectivity and obvious zwitterionic feature was synthesized successfully with the monomer allyglycine and the cross-linker 1, 3, 5-triacryloylhexahydro-1, 3, 5-triazine through in-situ copolymerization for capillary electrochromatography. The obtained monolithic column has good permeability. Due to the zwitterionic functional groups of allylglycine, the poly(AGly-co-TAT) monolithic column can generate a cathodic and anodic electroosmotic flow (EOF) by changing the mobile phase pH, which is beneficial to expand its application range. The separations of different series of polar analytes, thioureas, xanthines, phenols, peptides and acidic compounds are achieved on this hydrophilic monolithic column due to the powerful hydrophilic, electrostatic and hydrogen bond interactions. Using this monolithic column, hydrophilic separations are achieved even at a lower level of 50% organic solvent. The separation efficiency up to 1.41 × 105 N m-1 and 1.19 × 105 N m-1 is achieved for the separation of theophylline and phenol, respectively. For a real sample, cytochrome C digestion, the monolithic column shows good separation performance, which offers the potential application of the monolithic column on proteomics study.
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Affiliation(s)
- Zhenkun Mao
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China; State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing 10080, China
| | - Zhentao Li
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China
| | - Changjun Hu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China
| | - Yikun Liu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China
| | - Qiaoyan Li
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China
| | - Zilin Chen
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China; State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing 10080, China.
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30
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Cai Z, Hu X, Zong R, Wu H, Jin X, Yin H, Huang C, Xiang Y, Ye N. A graphene oxide-molybdenum disulfide composite used as stationary phase for determination of sulfonamides in open-tubular capillary electrochromatography. J Chromatogr A 2020; 1629:461487. [PMID: 32823013 DOI: 10.1016/j.chroma.2020.461487] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 08/12/2020] [Accepted: 08/13/2020] [Indexed: 11/26/2022]
Abstract
A graphene oxide-molybdenum disulfide (GO-MoS2) composite was synthesized and utilized as the highly efficient stationary phase of open-tubular capillary electrochromatography (OT-CEC). The characterization results indicated that GO-MoS2 composite was successfully synthesized. The GO-MoS2-coated capillary column was prepared by covalent immobilization method for the determination of seven sulfonamides. The baseline separation of seven sulfonamides was achieved by GO-MoS2-coated capillary column. The linear range was 0.05-100 μg/mL for sulfisomidine, sulfathiazole, sulfamerazine, phthalylsulfathiazole and sulfacetamide, 0.1-100 μg/mL for sulfamonomethoxine and sulfachloropyridazine with a satisfactory correlation coefficients (R2) > 0.9994. This developed OT-CEC method was successfully applied to determinate of seven sulfonamides in environmental water and milk samples with good recoveries of 85.77% - 109.10% and 80.03% - 109.97%, respectively. These results indicated that GO-MoS2-coated capillary column possessed good stability and repeatability.
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Affiliation(s)
- Zhimin Cai
- Department of Chemistry, Capital Normal University, Beijing, 100048, PR China
| | - Xiaoyu Hu
- Department of Chemistry, Capital Normal University, Beijing, 100048, PR China
| | - Rui Zong
- Department of Chemistry, Capital Normal University, Beijing, 100048, PR China
| | - Hanqing Wu
- College of Teacher Education, Capital Normal University, Beijing, 100048, PR China.
| | - Xiaotong Jin
- Department of Chemistry, Capital Normal University, Beijing, 100048, PR China
| | - Han Yin
- Department of Chemistry, Capital Normal University, Beijing, 100048, PR China
| | - Chuanlin Huang
- Department of Chemistry, Capital Normal University, Beijing, 100048, PR China
| | - Yuhong Xiang
- Department of Chemistry, Capital Normal University, Beijing, 100048, PR China
| | - Nengsheng Ye
- Department of Chemistry, Capital Normal University, Beijing, 100048, PR China.
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31
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Ma M, Du Y, Zhang L, Gan J, Yang J. β-Cyclodextrin covalent organic framework-modified organic polymer monolith as a stationary phase for combined hydrophilic and hydrophobic aqueous capillary electrochromatographic separation of small molecules. Mikrochim Acta 2020; 187:385. [PMID: 32533434 DOI: 10.1007/s00604-020-04360-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/31/2020] [Indexed: 12/23/2022]
Abstract
A β-Cyclodextrin covalent organic framework (β-CD COF) was successfully prepared under ambient temperature with a mild chemistry strategy from heptakis(6-amino-6-deoxy)-β-cyclodextrin and terephthalaldehyde. It was embedded into the poly[(glycidyl methacrylate)-co-(ethylene dimethacrylate)] [poly(GMA-co-EDMA)] monolith and served as the β-CD COF material-incorporated monolith. The synthetic materials were characterized by field emission scanning electron microscopy, energy-dispersive X-ray mapping analysis, transmission electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, and N2 adsorption-desorption isotherm. The β-CD COF material-incorporated monolith achieved baseline separation in capillary electrochromatographic separation of three amides, three amino acids, three nucleosides, four aromatic acids, and three positional isomers (with resolution values of three amides, 1.75 and 1.54; three amino acids, 5.24 and 1.75; three nucleosides, 2.56 and 1.77; four aromatic acids, 6.96, 2.74, and 1.64; three positional isomers, 1.61 and 1.50). In comparison with the original monolith, the β-CD COF material-incorporated monolith shows significantly enhanced resolution for mixed molecules. The effect of pH and concentration of buffer and applied voltage were discussed in detail. The fabricated monolith showed good stability and reproducibility (relative standard deviation (RSD) < 6.9%). Molecular modeling illuminated the interactions between the small molecules and stationary phase, and provided a sufficient theoretical basis for experimental data. Graphical abstract Schematic presentation of the preparation of β-cyclodextrin covalent organic framework (β-CD COF) material-incorporated organic polymer monolith for separating the amides, amino acids, nucleosides, aromatic acids, and positional isomers. β-CD COF materials were synthesized and incorporated into the monolith as the stationary phase. Then, the incorporated monolith was applied in the capillary electrochromatography system for separating small molecules.
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Affiliation(s)
- Mingxuan Ma
- Key Laboratory of Drug Quality Control and Pharmacovigilance (Ministry of Education), China Pharmaceutical University, No. 24 Tongjiaxiang, Nanjing, Jiangsu, 210009, People's Republic of China.,State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjiaxiang, Nanjing, Jiangsu, 210009, People's Republic of China
| | - Yingxiang Du
- Key Laboratory of Drug Quality Control and Pharmacovigilance (Ministry of Education), China Pharmaceutical University, No. 24 Tongjiaxiang, Nanjing, Jiangsu, 210009, People's Republic of China. .,State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjiaxiang, Nanjing, Jiangsu, 210009, People's Republic of China.
| | - Liu Zhang
- Key Laboratory of Drug Quality Control and Pharmacovigilance (Ministry of Education), China Pharmaceutical University, No. 24 Tongjiaxiang, Nanjing, Jiangsu, 210009, People's Republic of China.,State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjiaxiang, Nanjing, Jiangsu, 210009, People's Republic of China
| | - Jie Gan
- Key Laboratory of Drug Quality Control and Pharmacovigilance (Ministry of Education), China Pharmaceutical University, No. 24 Tongjiaxiang, Nanjing, Jiangsu, 210009, People's Republic of China.,State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjiaxiang, Nanjing, Jiangsu, 210009, People's Republic of China
| | - Jiangxia Yang
- Key Laboratory of Drug Quality Control and Pharmacovigilance (Ministry of Education), China Pharmaceutical University, No. 24 Tongjiaxiang, Nanjing, Jiangsu, 210009, People's Republic of China.,State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjiaxiang, Nanjing, Jiangsu, 210009, People's Republic of China
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Fan S, Guan J, Yan F, Zhang D, Shi S, Wang S. Preparation of open‐tubular CEC column bonded with 6‐O‐monotosyl‐deoxy‐β‐cyclodextrin and its application in the enantioseparation of several related benzimidazoles. SEPARATION SCIENCE PLUS 2020. [DOI: 10.1002/sscp.202000014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Shitong Fan
- School of Applied ChemistryShenyang University of Chemical Technology Shenyang P. R. China
| | - Jin Guan
- School of Applied ChemistryShenyang University of Chemical Technology Shenyang P. R. China
| | - Feng Yan
- School of Applied ChemistryShenyang University of Chemical Technology Shenyang P. R. China
| | - Dongxiang Zhang
- School of Applied ChemistryShenyang University of Chemical Technology Shenyang P. R. China
| | - Shuang Shi
- School of Applied ChemistryShenyang University of Chemical Technology Shenyang P. R. China
| | - Silin Wang
- School of Applied ChemistryShenyang University of Chemical Technology Shenyang P. R. China
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33
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Mao Z, Li Z, Hu C, Liu Y, Cao Z, Chen Z. Strong hydrophilic monolithic column functionalized with amphiphilic benzyl quinine for capillary electrochromatography and application in pharmaceutical analysis. J Chromatogr A 2020; 1621:461031. [PMID: 32201038 DOI: 10.1016/j.chroma.2020.461031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/05/2020] [Accepted: 03/10/2020] [Indexed: 12/27/2022]
Abstract
An innovative strong hydrophilic organic polymer monolithic column of poly(N-benzylquininium chloride-co-1, 3, 5-triacryloylhexahydro-1, 3, 5-triazine) (poly(NBQ-co-TAT)) has been successfully synthesized through in situ copolymerization for capillary electrochromatography. The amphiphilic monomer NBQ and the strong polar cross-linker TAT are firstly used in hydrophilic electrochromatography by taking advantage of the exhibition of hydrophilicity at lower levels of organic solvent and ease formation of porous structure. The monolithic column poly(NBQ-co-TAT) shows powerful hydrophilic selectivity with mobile phase containing more than 60% organic solvent. The introduction of NBQ and TAT enlarges the sources of functional monomers and cross-linkers for HILIC. Due to the presence of the positively charged group in NBQ, an anodic electroosmotic flow is generated with the change of pH values from 2.0 to 12.0. The monolithic column was used for the separations of thioureas, phenols, xanthines, nucleobases, acidic substances and pharmaceuticals. The highest column efficiency for N, N'-dimethylthiourea is 1.15 × 105 N m-1. The application of the monolithic column for a real sample, cytochrome C digestion indicates its great potential in practical application.
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Affiliation(s)
- Zhenkun Mao
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China; State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing 10080, China
| | - Zhentao Li
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China
| | - Changjun Hu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China
| | - Yikun Liu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China
| | - Zhi Cao
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China
| | - Zilin Chen
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China; State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing 10080, China.
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Chernikova EY, Berdnikova DV, Peregudov AS, Fedorova OA, Fedorov YV. Encapsulation-Controlled Photoisomerization of a Styryl Derivative: Stereoselective Formation of the Anti Z-Isomer in the Cucurbit[7]uril Cavity. Chemphyschem 2020; 21:442-449. [PMID: 31863708 DOI: 10.1002/cphc.201901095] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/20/2019] [Indexed: 02/04/2023]
Abstract
The photochemical isomerization of a styrylpyridinium dye (SP) bearing an unsymmetrically attached benzo-15-crown-5 ether has been studied in aqueous solution in the absence and presence of cucurbit[7]uril (CB[7]). The detailed analysis of the UV/Vis and NMR spectra showes that the isomeric composition of the photostationary mixtures of SP can be modulated by the host-guest complexation with CB[7]. It was found that steric hindrance caused by encapsulation of SP in the host cavity induces the exclusive formation of the anti conformer of Z-SP in contrast with the mixture of both anti and syn conformers obtained during photoisomerization of the dye without CB[7]. Remarkably, the displacement of anti Z-SP from CB[7] does not lead to the transformation of the anti Z-isomer into the syn Z-isomer pointing out the conformational memory of the system. The results provide an interesting example of the supramolecular stereorecognition by the achiral CB[7] host.
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Affiliation(s)
- Ekaterina Y Chernikova
- Laboratory of Photoactive Supramolecular Systems, A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Science, Vavilova st. 28, 119991, Moscow, Russia
| | - Daria V Berdnikova
- Universität Siegen, Organische Chemie II, Adolf-Reichwein-Str. 2, 57076, Siegen, Germany
| | - Alexander S Peregudov
- Laboratory of Nuclear Magnetic Resonances, A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Science, Vavilova st. 28, 119991, Moscow, Russia
| | - Olga A Fedorova
- Laboratory of Photoactive Supramolecular Systems, A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Science, Vavilova st. 28, 119991, Moscow, Russia
| | - Yuri V Fedorov
- Laboratory of Photoactive Supramolecular Systems, A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Science, Vavilova st. 28, 119991, Moscow, Russia
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Zhao L, Lv W, Niu X, Pan C, Chen H, Chen X. An azine-linked covalent organic framework as stationary phase for separation of environmental endocrine disruptors by open-tubular capillary electrochromatography. J Chromatogr A 2020; 1615:460722. [DOI: 10.1016/j.chroma.2019.460722] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 11/06/2019] [Accepted: 11/16/2019] [Indexed: 01/02/2023]
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36
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Bernardo-Bermejo S, Sánchez-López E, Castro-Puyana M, Marina ML. Chiral capillary electrophoresis. Trends Analyt Chem 2020. [DOI: 10.1016/j.trac.2020.115807] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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37
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Open-tubular admicellar electrochromatography of charged analytes. Talanta 2020; 208:120401. [PMID: 31816751 DOI: 10.1016/j.talanta.2019.120401] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 09/26/2019] [Accepted: 09/27/2019] [Indexed: 11/23/2022]
Abstract
Fundamental studies on the separation of cationic and anionic analytes in open-tubular admicellar electrochromatography (OT-AMEC) using cetyltrimethylammonium bromide (CTAB) and fused silica capillaries are presented. OT-AMEC was compared with open-tubular admicellar liquid chromatography (OT-AMLC) by running the two methods using the same mobile phases. The mobile phases were buffered at pH ≥ 6 and contained a low concentration (above the critical surface aggregation concentration and below the critical micelle concentration) of CTAB. The stationary pseudophase of CTAB admicelles were formed at the solid surface and liquid interface inside the capillary by simply conditioning the capillary with the mobile phase. Separations were performed in a 30 cm (21.5 cm to UV detector) long and 50 μm inner diameter capillary, using low pressure (50 mbar) in OT-AMLC and high voltage (15 kV at negative polarity) in OT-AMEC. The appropriate equations for the experimental estimation of retention factor (k) values of analytes were discussed. For anionic analytes, k in OT-AMEC were carefully determined by considering the observed interaction between CTAB monomers and tested analytes. The calculated k for each analyte was found similar in OT-AMLC and OT-AMEC, although the mechanism of retention was not entirely different due to the contribution of electrophoresis in OT-AMEC. Studies on the addition of a typical (i.e., acetonitrile) and atypical modifier (i.e., nonyl-β-glucoside) into the mobile phase, and sample focusing with >10x improvement in peak height under isocratic conditions were also conducted.
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