1
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Rapid Separation and Determination of Metronidazole Benzoate and Other Antiprotozoal Drugs by Pressurized Capillary Electrochromatography. J CHEM-NY 2018. [DOI: 10.1155/2018/8953296] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
A novel method for the rapid separation and determination of five polar 5-nitroimidazoles in water from different sources by pressurized capillary electrochromatography has been developed. Compared with the gradient elution mode and the packed nonpolar columns which were usually utilized for the separation of 5-nitroimidazoles, a simple isocratic elution mode and low-cost homemade polar molecularly imprinted polymer monolith were used in the experiment. Electrochromatographic conditions such as pH of buffer, organic modifier, concentration of buffer, and separation voltage were optimized. At 320 nm UV wavelengths, the five 5-nitroimidazoles could be baseline-separated rapidly in less than 11 min with the separation voltage of +20 kV in 10 mmol/L sodium dihydrogen phosphate-disodium hydrogen phosphate buffer solution (pH 4.82) containing 30% acetonitrile. Under the optimum conditions, the linear ranges of the metronidazole, secnidazole, tinidazole, ornidazole, and metronidazole benzoate were 0.50–100.00, 0.50–100.00, 0.80–500.00, 0.80–100.00, and 5.00–500.00 μg/mL, respectively, and the detection limits of these analytes were 0.11–0.73 μg/mL. Column efficiencies of 43 000, 36 000, 34 000, 14 000, and 29 000 plates/m were obtained for metronidazole, secnidazole, tinidazole, ornidazole, and metronidazole benzoate, respectively. The recoveries of different water samples were about 85.0–95.8%. Additionally, the proposed method has been successfully applied to the rapid separation of 5-nitroimidazoles in the locally available pure milk sample by simple pretreatment.
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2
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Bol’shakova DS, Amelin VG. Determination of pesticides in environmental materials and food products by capillary electrophoresis. JOURNAL OF ANALYTICAL CHEMISTRY 2016. [DOI: 10.1134/s1061934816100026] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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3
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D'Orazio G, Asensio-Ramos M, Fanali C, Hernández-Borges J, Fanali S. Capillary electrochromatography in food analysis. Trends Analyt Chem 2016. [DOI: 10.1016/j.trac.2016.06.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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4
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Wang J, Wu F, Xia R, Zhao Q, Lin X, Xie Z. Rapid fabrication of ionic liquid-functionalized monolithic column via in-situ urea-formaldehyde polycondensation for pressurized capillary electrochromatography. J Chromatogr A 2016; 1449:100-8. [DOI: 10.1016/j.chroma.2016.04.069] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 04/21/2016] [Accepted: 04/25/2016] [Indexed: 12/22/2022]
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5
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Ma H, Feng W, Tian M, Jia Q. Determination of N-methylcarbamate pesticides in vegetables by poly(methacrylic acid-co-ethylene glycol dimethacrylate) monolith microextraction coupled with high performance liquid chromatography. J Chromatogr B Analyt Technol Biomed Life Sci 2013; 929:27-32. [DOI: 10.1016/j.jchromb.2013.01.036] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 01/24/2013] [Accepted: 01/30/2013] [Indexed: 10/27/2022]
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6
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Santaladchaiyakit Y, Srijaranai S, Burakham R. Methodological aspects of sample preparation for the determination of carbamate residues: A review. J Sep Sci 2012; 35:2373-89. [DOI: 10.1002/jssc.201200431] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Yanawath Santaladchaiyakit
- Department of Chemistry; Faculty of Engineering; Rajamangala University of Technology Isan; KhonKaen Thailand
| | - Supalax Srijaranai
- Materials Chemistry Research Unit; Department of Chemistry and Center of Excellence for Innovation in Chemistry; Faculty of Science, KhonKaen University; KhonKaen Thailand
| | - Rodjana Burakham
- Materials Chemistry Research Unit; Department of Chemistry and Center of Excellence for Innovation in Chemistry; Faculty of Science, KhonKaen University; KhonKaen Thailand
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Wang M, Feng R, Shen J, Chen H, Zeng Z. Capillary Electrochromatography with Liquid Crystal Crown Ether Modified Hybrid Silica Monolith for Analysis of Imidacloprid and Carbendazim in Tomatoes. B KOREAN CHEM SOC 2012. [DOI: 10.5012/bkcs.2012.33.7.2224] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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8
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Li Y, Qi L, Qiao J, Shen Y, Yan H, Xin P, Ma H. A well-defined block copolymer serving as surfactants in separation of 1,4-dihydropyridines by open-tubular capillary eletrochromatography. Electrophoresis 2012; 33:2019-27. [DOI: 10.1002/elps.201100548] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | - Li Qi
- Beijing National Laboratory of Molecular Sciences; Key Laboratory of Analytical Chemistry for Living Biosystems; Institute of Chemistry, Chinese Academy of Sciences; Beijing; China
| | - Juan Qiao
- Beijing National Laboratory of Molecular Sciences; Key Laboratory of Analytical Chemistry for Living Biosystems; Institute of Chemistry, Chinese Academy of Sciences; Beijing; China
| | | | - Huijuan Yan
- Beijing National Laboratory of Molecular Science; Key Laboratory of Molecular Nanostructure and Nanotechnology; Institute of Chemistry; Chinese Academy of Sciences; Beijing; China
| | | | - Huimin Ma
- Beijing National Laboratory of Molecular Sciences; Key Laboratory of Analytical Chemistry for Living Biosystems; Institute of Chemistry, Chinese Academy of Sciences; Beijing; China
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Hsu CH, Hu CC, Chiu TC. Analysis of carbofuran, carbosulfan, isoprocarb, 3-hydroxycarbofuran, and 3-ketocarbofuran by micellar electrokinetic chromatography. J Sep Sci 2012; 35:1359-64. [DOI: 10.1002/jssc.201101108] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Chien-Hua Hsu
- Department of Applied Science, National Taitung University; Taitung; Taiwan
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Wang X, Zheng Y, Zhang C, Yang Y, Lin X, Huang G, Xie Z. Preparation and characterization of hybrid-silica monolithic column with mixed-mode of hydrophilic and strong anion-exchange interactions for pressurized capillary electrochromatography. J Chromatogr A 2012; 1239:56-63. [PMID: 22503622 DOI: 10.1016/j.chroma.2012.03.071] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2011] [Revised: 03/19/2012] [Accepted: 03/22/2012] [Indexed: 11/27/2022]
Abstract
A novel organic-silica hybrid monolithic stationary phase with a mixed-mode of hydrophilic and strong anion-exchange interactions (HI-SAX) was prepared with a modified "one-pot" process of functional monomers and alkoxysilanes. Using a hydrosoluble initiator 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AIBA), the homogeneous prepolymerization system of this hybrid monolith was successfully obtained by a simple operation. The polycondensation of alkoxysilanes (tetramethoxysilane (TMOS) and vinyl-trimethoxysilane (VTMS)) and the in situ copolymerization of a quaternary ammonium group-containing acrylic monomer ([2-(acryloyloxy)ethyl] trimethyl ammonium methyl sulfate (AETA)) on the precondensed siloxanes were achieved. The morphologies of the hybrid-silica monolithic matrixes were observed by SEM, and the performances of the organic-silica hybrid monolithic columns were investigated by pressurized capillary electrochromatography. The mechanical stability and reproducibility of the obtained hybrid monolithic column preformed acceptable. Both hydrophilic interaction chromatography mechanism and strong anion-exchanged interaction were investigated. A mixed mode of HI-SAX was obtained for the analysis of nucleotides with a good resolution, and the separation of polar and basic nucleic acid bases and nucleosides was also achieved without peak tailing.
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Affiliation(s)
- Xiao Wang
- Institute of Food Safety and Environmental Monitoring, Fuzhou University, Fuzhou, 350108, China
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11
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Use of dispersive liquid–liquid microextraction for the determination of carbamates in juice samples by sweeping-micellar electrokinetic chromatography. Anal Bioanal Chem 2011; 400:1329-38. [DOI: 10.1007/s00216-011-4682-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 01/13/2011] [Accepted: 01/13/2011] [Indexed: 10/18/2022]
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12
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Wang J, Chen D, Chen Z, Fan G, Wu Y. Fast separation and determination of coumarins in Fructus cnidii extracts by CEC using poly(butyl methacrylate-co-ethylene dimethacrylate-co-[2-(methacryloyloxy)ethyl] trimethylammonium chloride) monolithic columns. J Sep Sci 2010; 33:1099-108. [PMID: 20187027 DOI: 10.1002/jssc.200900657] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A rapid CEC method with poly(butyl methacrylate-co-ethylene dimethacrylate-co-[2-(methacryloyloxy)ethyl] trimethylammonium chloride) monolithic column has been developed for separation and determination of four coumarins (isopimpinelline, bergapten, imperatorin, and osthole) in Fructus cnidii extracts. The effect of polymerization condition including the monomers ratio and the porogens ratio were studied. The mobile-phase composition, such as the composition of organic solvent, the concentration and pH of buffer, was also optimized. Under the same condition (50% ACN and 50% of a 10 mM sodium dihydrogen phosphate electrolyte at pH 4.95), in contrast to 25 min of analysis time in HPLC and 10 min of analysis time in pCEC, a fast separation of these analytes was achieved in less than 5 min in CEC. Method validation was developed in accordance with the analytical procedures. Intra- and interday precisions (RSD) for relative retention time and peak area were less than 1.69 and 4.63%, and LODs were lower than 0.5 microg/mL. Calibration curves of four compounds also showed good linearity (r(2)>0.995). The mean recoveries ranged between 93.91 and 98.65%. With this CEC system, the quality of F. cnidii extracts from various resources was evaluated by determining the contents of the four coumarins.
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Affiliation(s)
- Jiajing Wang
- Department of Pharmaceutical Analysis, School of Pharmacy, Second Military Medical University, Shanghai, PR China
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13
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Liao S, Wang X, Lin X, Xie Z. Preparation and characterization of a molecularly imprinted monolithic column for pressure-assisted CEC separation of nitroimidazole drugs. Electrophoresis 2010; 31:2822-30. [DOI: 10.1002/elps.201000035] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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14
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Lin Z, Pang J, Huang H, Zhang L, Chen G. [Recent advances in capillary electrochromatography and its coupling techniques]. Se Pu 2010; 28:273-83. [PMID: 20549979 DOI: 10.3724/sp.j.1123.2010.00273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
As a novel micro-separation technique, capillary electrochromatography (CEC) has the merits of high efficiency, high selectivity, high resolution and rapid analysis. However, the small-volume injection manipulated in capillary dimensions poses a great challenge for detectors in achieving high sensitivity. Currently, one of the major researches into CEC involves the development of some sensitive detection modes. The general introduction, which includes the historical perspectives and the principles of CEC, is briefly described. The recent advances about CEC coupled with various detectors and its applications in the separation of complex samples are summarized. A total of 141 references are reviewed.
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Affiliation(s)
- Zian Lin
- Key Laboratory of Analysis and Detection Technology for Food Safety of Ministry of Education, College of Chemistry & Chemical Engineering, Fuzhou University, Fuzhou 350002, China.
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15
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Qu Q, Peng S, Mangelings D, Hu X, Yan C. Silica spheres coated with C18-modified gold nanoparticles for capillary LC and pressurized CEC separations. Electrophoresis 2010; 31:556-62. [PMID: 20119965 DOI: 10.1002/elps.200900375] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Nonporous monodispersed silica spheres of 1.3 microm were coated with gold nanoparticles (AuNPs) and subsequently coated with n-octadecanethiol. By transmission electron microscopy analysis, the average diameter of the AuNPs on the silica spheres was determined to be 12 nm. The chromatographic and electrochromatographic properties of self-assembled n-octadecanethiol AuNP-coated silica microspheres (C18-AuNPs-SiO2) were investigated using a group of nonpolar PAHs. The stationary phase appears to display a characteristic reversed-phase behavior. Higher separation efficiency and shorter separation times were obtained using pressurized CEC (pCEC) compared with capillary LC (CLC). A maximum column efficiency of about 2.5x10(5) plates per meter and less than 18 min separation time for benzene were obtained in pCEC while only 66 507 plates per meter and an analysis time of nearly 100 min were observed in CLC mode. A chemical stability test of the C18-AuNPs-SiO2 stationary phase under extremely high and low pH conditions demonstrated that it is stable at pH 12 and 1 for at least 60 h. The results confirm that C18-AuNPs-SiO2 possesses a high rigidity to withstand high packing pressures and can be used as a good stationary phase for CLC and pCEC.
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Affiliation(s)
- Qishu Qu
- College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, PR China.
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Lin J, Lin J, Lin X, Wu X, Xie Z. Preparation of a neutral porous monolith and its evaluation in pressurized capillary electrochromatography with neutral and charged solutes. Electrophoresis 2010; 31:1674-80. [DOI: 10.1002/elps.200900669] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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17
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Gu C, He J, Jia J, Fang N, Shamsi SA. Surfactant-bound monolithic columns for CEC. Electrophoresis 2010; 30:3814-27. [PMID: 19885887 DOI: 10.1002/elps.200900434] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A novel anionic surfactant bound monolithic stationary phase based on 11-acrylaminoundecanoic acid is designed for CEC. The monolith possessing bonded undecanoyl groups (hydrophobic sites) and carboxyl groups (weak cationic ion-exchange sites) were evaluated as a mixed-mode stationary phase in CEC for the separation of neutral and polar solutes. Using a multivariate D-optimal design the composition of the polymerization mixture was modeled and optimized with five alkylbenzenes and seven alkyl phenyl ketones as test solutes. The D-optimal design indicates a strong dependence of electrochromatographic parameters on the concentration of 11-acrylaminoundecanoic acid monomer and porogen (water) in the polymerization mixture. A difference of 6, 8 and 13% RSD between the predicted and the experimental values in terms of efficiency, resolution and retention time, respectively, indeed confirmed that the proposed approach is practical. The physical (i.e. morphology, porosity and permeability) and chromatographic properties of the monolithic columns were thoroughly investigated. With the optimized monolithic column, high efficiency separation of N-methylcarbamates pesticides and positional isomers was successfully achieved. It appears that this type of mixed-mode monolith (containing both chargeable and hydrophobic sites) may have a great potential as a new generation of CEC stationary phase.
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Affiliation(s)
- Congying Gu
- Department of Chemistry, Center for Biotechnology and Drug Design, Georgia State University, Atlanta, GA 30303, USA
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18
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Wu W, Wu Y, Zheng M, Yang L, Wu X, Lin X, Xie Z. Pressurized capillary electrochromatography with indirect amperometric detection for analysis of organophosphorus pesticide residues. Analyst 2010; 135:2150-6. [DOI: 10.1039/c0an00101e] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wang X, Lin X, Xie Z. Preparation and evaluation of a sulfoalkylbetaine-based zwitterionic monolithic column for CEC of polar analytes. Electrophoresis 2009; 30:2702-10. [DOI: 10.1002/elps.200900006] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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20
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Li M, Lin X, Xie Z. Investigation of enantiomer recognition of molecularly imprinted polymeric monoliths in pressurized capillary electrochromatography screening the amino acids and their derivatives. J Chromatogr A 2009; 1216:5320-6. [DOI: 10.1016/j.chroma.2009.05.012] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Revised: 05/05/2009] [Accepted: 05/08/2009] [Indexed: 11/16/2022]
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21
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Wu W, Wu X, Lin X, Xie Z, Giesy JP. Quantification of domoic acid in shellfish tissues by pressurized capillary electrochromatography. J Sep Sci 2009; 32:2117-22. [DOI: 10.1002/jssc.200900017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Preparation and evaluation of a neutral methacrylate-based monolithic column for hydrophilic interaction stationary phase by pressurized capillary electrochromatography. J Chromatogr A 2009; 1216:4611-7. [DOI: 10.1016/j.chroma.2009.03.057] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2008] [Revised: 01/05/2009] [Accepted: 03/20/2009] [Indexed: 11/20/2022]
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23
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Lin J, Huang G, Lin X, Xie Z. Methacrylate-based monolithic column with mixed-mode hydrophilic interaction/strong cation-exchange stationary phase for capillary liquid chromatography and pressure-assisted CEC. Electrophoresis 2009; 29:4055-65. [PMID: 18958876 DOI: 10.1002/elps.200800084] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A novel porous polymethacrylate-based monolithic column by in situ copolymerization of 3-sulfopropyl methacrylate (SPMA) and pentaerythritol triacrylate in a binary porogenic solvent consisting of cyclohexanol/ethylene glycol was prepared. The monolith possessed in their structures bonded sulfonate groups and hydroxyl groups and was evaluated as a hydrophilic interaction and strong cation-exchange stationary phases in capillary liquid chromatography (cLC) and pressure-assisted CEC using small polar neutral and charged solutes. While the SPMA was introduced as multifunctional monomer, the pentaerythritol triacrylate was used to replace ethylene glycol dimethacrylate as cross-linker with much more hydrophilicity due to a hydroxyl sub-layer. The different characterization of monolithic stationary phases were specially designed and easily prepared by altering the amount of SPMA in the polymerization solution as well as the composition of the porogenic solvent for cLC and pressure-assisted CEC. The resulting monolith showed the different trends about the effect of the permeabilities on efficiency in the pressure-assisted CEC and cLC modes. A typical hydrophilic interaction chromatography mechanism was observed at higher organic solvent content (ACN%>70%) for polar neutral analytes. For polar charged analytes, both hydrophilic interaction and electrostatic interaction contributed to their retention. Therefore, for charged analytes, selectivity can be readily manipulated by changing the composition of the mobile phase (e.g., pH, ionic strength and organic modifier). With the optimized monolithic column, high plate counts reaching greater than 170 000 plates/m for pressure-assisted CEC and 105 000 plates/m for cLC were easily obtained, respectively.
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Affiliation(s)
- Jian Lin
- Department of Chemistry, Fuzhou University, Fuzhou, PR China
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Huang G, Lian Q, Zeng W, Xie Z. Preparation and evaluation of a lysine-bonded silica monolith as polar stationary phase for hydrophilic interaction pressurized capillary electrochromatography. Electrophoresis 2008; 29:3896-904. [PMID: 18850658 DOI: 10.1002/elps.200700949] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A silica-based monolith as polar stationary phase was described for hydrophilic interaction pressurized capillary electrochromatography (HI-pCEC). The polar monolithic column was prepared by on-column reaction of lysine with epoxy groups on a gamma-glycidoxypropyltrimethosysilane-modified silica monolith. The stationary phase yielded strong hydrophilic interaction due to the slightly polar hydroxyl groups, and the strong polar lysine ligand with amino groups and carboxylic groups contained on the surface of the monolith. In order to evaluate the hydrophilic character of lysine ligand, the chromatographic behaviors of epoxy monolith (before lysine bonded) and diol monolith (hydroxyl groups contained) were also investigated. Two groups of comparative experiment were developed in terms of the separation of typical neutral non-polar and polar compounds performed in a mobile phase of aqueous-acetonitrile solution. Results showed that the lysine monolith was much more hydrophilic than the diol monolith, which presented less hydrophobic than the epoxy monolith. For further study on its hydrophilic character, the lysine monolith was demonstrated in the HI-pCEC mode for the separations of various polar compounds such as phenols, nucleic acid bases and nucleosides.
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Affiliation(s)
- Guihua Huang
- Department of Chemistry, Fuzhou University, Fuzhou, P. R. China
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Rapid separation and determination of microcystins using monolithic columns in isocratic elution mode by pressurized capillary electrochromatography. Electrophoresis 2008; 29:3887-95. [DOI: 10.1002/elps.200700944] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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26
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Wang X, Lü H, Lin X, Xie Z. Electrochromatographic characterization of methacrylate-based monolith with mixed mode of hydrophilic and weak electrostatic interactions by pressurized capillary electrochromatography. J Chromatogr A 2008; 1190:365-71. [DOI: 10.1016/j.chroma.2008.02.106] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2007] [Revised: 02/21/2008] [Accepted: 02/29/2008] [Indexed: 11/24/2022]
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Wei H, Sun JJ, Wang YM, Li X, Chen GN. Rapid hydrolysis and electrochemical detection of trace carbofuran at a disposable heated screen-printed carbon electrode. Analyst 2008; 133:1619-24. [DOI: 10.1039/b806750c] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Boyce MC. Determination of additives and organic contaminants in food by CE and CEC. Electrophoresis 2007; 28:4046-62. [DOI: 10.1002/elps.200700280] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Lü H, Wang J, Wang X, Wu X, Lin X, Xie Z. Single-step preparation and characterization of polymeric monolith for pressurized capillary electrochromatography of typical homologs. J Sep Sci 2007; 30:2993-9. [PMID: 17880031 DOI: 10.1002/jssc.200700220] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A monolithic stationary phase was prepared in a single step by in situ copolymerization of iso-butyl methacrylate (IBMA), ethylene dimethacrylate (EDMA), and N,N-dimethylallylamine (DMAA) in a binary porogenic solvent consisting of N,N-dimethylformamide (DMF) and 1,4-butanediol. As the frame structures of monoliths, the amino groups are linked to support the EOF necessary for driving the mobile phase through the monolithic capillary, while the hydrophobic groups are introduced to provide the nonpolar sites for the chromatographic retention. To evaluate the column performance, separations of typical kinds of neutral or charged homologs, such as alkylbenzenes, phenols (including isomeric compounds of hydroquinone, resorcin, and catechol), and anilines (including isomeric compounds of o-phenylenediamine and 1,4-phenylenediamine), were performed, respectively on the prepared column under the mode of pressurized pCEC. Effects of the buffer pH and the mobile phase composition on the linear velocity of mobile phase and the retention factors of these compounds were investigated. It was found that the retention mechanism of charged solutes could be attributed to a mixed mode of hydrophobic interaction and electrophoresis, while an RP chromatographic behavior on the monolithic stationary phases was exhibited for neutral solutes. Especially, basic compounds such as anilines were well separated on the monolithic columns in the "counterdirectional mode," which effectively eliminated the electrostatic adsorption of basic analytes on the charged surface of the stationary phases.
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Affiliation(s)
- Haixia Lü
- College of Materials Science and Engineering, Fuzhou University, Fuzhou, Fujian, China
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Liu S, Zhang X, Lin X, Wu X, Fu F, Xie Z. Development of a new method for analysis of Sudan dyes by pressurized CEC with amperometric detection. Electrophoresis 2007; 28:1696-703. [PMID: 17465422 DOI: 10.1002/elps.200600486] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A new analytical method, pressurized CEC (pCEC) with amperometric detection (AD) using 1.5 microm RP nonporous silica packed columns has been developed for the rapid separation and determination of four Sudan dyes in hot chilli. The influence of several experimental parameters on the retention behavior has been investigated. The electrochemical oxidation of Sudans I-IV separated by pCEC can be reliably monitored with a carbon electrode at +0.95 V (vs. Ag/AgCl). Fast and efficient separation of the analytes was achieved within 7 min by pCEC under the optimum conditions with an ACN/water (95:5%) mobile phase containing formic acid (pH 4.3), 5% acetone and 0.002% triethylamine using a separation voltage of 12 kV. The detection limits for four Sudan dyes ranged from 8.0 x 10(-7) to 1.2 x 10(-6) mol/L. To evaluate the feasibility and reliability of this method, the proposed pCEC-AD method was further demonstrated with hot chilli samples spiked with Sudan dyes.
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Affiliation(s)
- Shaofeng Liu
- The Key Laboratory of Analysis and Detection Technology for Food Safety (Fuzhou University), Ministry of Education, Department of Chemistry, Fuzhou University, Fuzhou, Fujian, China
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Determination of Endogenous Metabolites in Obesity Rat Urine by Pressurized Capillary Electrochromatography with Ethyl Chloroformate Derivatization. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2007. [DOI: 10.1016/s1872-2040(07)60073-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Lin B, Zheng MM, Ng SC, Feng YQ. Development of in-tube solid-phase microextraction coupled to pressure-assisted CEC and its application to the analysis of propranolol enantiomers in human urine. Electrophoresis 2007; 28:2771-80. [PMID: 17577883 DOI: 10.1002/elps.200700174] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A successful hyphenation of in-tube solid-phase microextraction (SPME) and pressure-assisted CEC (pCEC) was developed by installing a poly(methacrylic acid-co-ethylene glycol dimethacrylate) monolithic capillary to the six-port valve in a CEC system. The device designed was appropriate for on-line in-tube SPME coupled to pCEC or muHPLC. The evaluation of this hyphenation was first carried out for in-tube SPME-muHPLC with analytical capillaries packed with 3 microm octadecyl silica (ODS). Theobromine (TB), theophylline (TP), and caffeine (CA) were chosen as model drugs for an easy comparison with the results obtained by in tube SPME-HPLC. The detection limits of these three analytes were improved more than 100 times when compared with the direct analysis by muHPLC. Then in-tube SPME-pCEC with CEC capillaries packed with perphenylcarbamoylated beta-CD-bonded silica particles was applied to the determination and analysis of propranolol enantiomers in human urine. Under optimal extraction and separation conditions, the experimental LODs were 4 and 7 ng/mL for (S)-propranolol and (R)-propranolol, respectively. The calibration curves showed good linearity for both (S)-propranolol (R(2) = 0.9997) and (R)-propranolol (R(2) = 0.9996) over the concentration range from 20 to 5000 ng/mL. Reproducibility of the method was also investigated with intra- and interday precisions lower than 10% for both enantiomers at different concentration levels.
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Affiliation(s)
- Bo Lin
- Department of Chemistry, Wuhan University, Wuhan, P. R. China
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