1
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Vigh G, Gas B. Evolution of the theoretical description of the isoelectric focusing experiment: I. The path from Svensson's steady-state model to the current two-stage model of isoelectric focusing. Electrophoresis 2023; 44:667-674. [PMID: 36640145 DOI: 10.1002/elps.202200236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 12/29/2022] [Accepted: 01/05/2023] [Indexed: 01/15/2023]
Abstract
In 1961, Svensson described isoelectric focusing (IEF), the separation of ampholytic compounds in a stationary, natural pH gradient that was formed by passing current through a sucrose density gradient-stabilized ampholyte mixture in a constant cross-section apparatus, free of mixing. Stable pH gradients were formed as the electrophoretic transport built up a series of isoelectric ampholyte zones-the concentration of which decreased with their distance from the electrodes-and a diffusive flux which balanced the generating electrophoretic flux. When polyacrylamide gel replaced the sucrose density gradient as the stabilizing medium, the spatial and temporal stability of Svensson's pH gradient became lost, igniting a search for the explanation and mitigation of the loss. Over time, through a series of insightful suggestions, the currently held notion emerged that in the modern IEF experiment-where the carrier ampholyte (CA) mixture is placed between the anolyte- and catholyte-containing large-volume electrode vessels (open-system IEF)-a two-stage process operates that comprises a rapid first phase during which a linear pH gradient develops, and a subsequent slow, second stage, during which the pH gradient decays as isotachophoretic processes move the extreme pI CAs into the electrode vessels. Here we trace the development of the two-stage IEF model using quotes from the original publications and point out critical results that the IEF community should have embraced but missed. This manuscript sets the foundation for the companion papers, Parts 2 and 3, in which an alternative model, transient bidirectional isotachophoresis is presented to describe the open-system IEF experiment.
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Affiliation(s)
- Gyula Vigh
- Chemistry Department, Texas A&M University, College Station, Texas, USA
| | - Bohuslav Gas
- Faculty of Science, Charles University, Prague, Czech Republic
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2
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Zhang Q, Guo Z, Luo F, Xiao H, Liu W, Fan L, Cao C. Model, Simulation, and Experiments on Moving Exchange Boundary via Ligand and Quantum Dots in Chip Electrophoresis. Anal Chem 2021; 93:5360-5364. [PMID: 33754711 DOI: 10.1021/acs.analchem.1c00242] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Herein, the quench model of the moving exchange boundary (MEB) was first created via a ligand of 5,5'-dithiobis(2-nitro-benzoic acid) (DTNB) and group of 3-mercaptopropionic acid (MPA) capped on QDs, and then the recovery model was formed via MPA and 2-nitro-5-thiobenzoic acid (TNB) capped on QDs. The theory on MEB dynamics and width was developed based on the two reversible models, the simulation was conducted for the illumination of MEB, and the protocol was described for the MEB runs. The experiments revealed that (i) the quench model could be created via DTNB and MPA capped on QDs and the recovery one could be in situ formed via MPA and TNB capped on QDs, showing the feasibility of MEB models; (ii) the simulations on MEB dynamics and width were in coincidence with the theoretic predictions, showing the validity of two models; and (iii) the experiments demonstrated the validity of models, predictions, and simulations. The models and theory have potential for development of a biosensor, nanoparticle characterization, separation science, and an affinity assay of ligand-QDs.
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Affiliation(s)
- Qiang Zhang
- Department of Instrument Science and Engineering, School of Electronic Information & Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zehua Guo
- Department of Instrument Science and Engineering, School of Electronic Information & Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Fang Luo
- School of Life Science and Biotechnology, State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hua Xiao
- School of Life Science and Biotechnology, State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Weiwen Liu
- Department of Instrument Science and Engineering, School of Electronic Information & Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Liuyin Fan
- Student Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Chengxi Cao
- Department of Instrument Science and Engineering, School of Electronic Information & Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.,School of Life Science and Biotechnology, State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China.,Shanghai Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai 200240, China
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3
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Chen L, Zhang Q, Liu W, Xiao H, Liu X, Fan L, Wang Y, Li H, Cao C. A facile thermometer-like electrophoresis titration biosensor for alternative miRNA assay via moving reaction boundary chip. Biosens Bioelectron 2021; 171:112676. [DOI: 10.1016/j.bios.2020.112676] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/14/2020] [Accepted: 10/01/2020] [Indexed: 01/07/2023]
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4
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Isoelectric focusing array with immobilized pH gradient and dynamic scanning imaging for diabetes diagnosis. Anal Chim Acta 2019; 1063:178-186. [DOI: 10.1016/j.aca.2019.03.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 03/02/2019] [Accepted: 03/07/2019] [Indexed: 12/24/2022]
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5
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Mikhail IE, Tehranirokh M, Gooley AA, Guijt RM, Breadmore MC. In-Syringe Electrokinetic Ampholytes Focusing Coupled with Electrospray Ionization Mass Spectrometry. Anal Chem 2019; 91:8259-8266. [DOI: 10.1021/acs.analchem.9b00942] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Ibraam E. Mikhail
- ARC Training Centre for Portable
Analytical Separation Technologies (ASTech)
- Australian Centre for Research on Separation Science (ACROSS), School of Natural Sciences (Chemistry), University of Tasmania, Private Bag 75, Hobart, Tasmania 7001, Australia
- Department of Analytical Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura City 35516, Egypt
| | - Masoomeh Tehranirokh
- ARC Training Centre for Portable
Analytical Separation Technologies (ASTech)
- Trajan Scientific and Medical, Ringwood, Victoria 3134, Australia
| | - Andrew A. Gooley
- ARC Training Centre for Portable
Analytical Separation Technologies (ASTech)
- Trajan Scientific and Medical, Ringwood, Victoria 3134, Australia
| | - Rosanne M. Guijt
- ARC Training Centre for Portable
Analytical Separation Technologies (ASTech)
- Deakin University, Centre for Regional and Rural Futures, Geelong, Victoria 3220, Australia
| | - Michael C. Breadmore
- ARC Training Centre for Portable
Analytical Separation Technologies (ASTech)
- Australian Centre for Research on Separation Science (ACROSS), School of Natural Sciences (Chemistry), University of Tasmania, Private Bag 75, Hobart, Tasmania 7001, Australia
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6
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Luo A, Zheng Y, Chen X, Cong F. Undergraduate laboratory experiment on determination of total protein content in milk powder by moving reaction boundary titration. BIOCHEMISTRY AND MOLECULAR BIOLOGY EDUCATION : A BIMONTHLY PUBLICATION OF THE INTERNATIONAL UNION OF BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 46:644-651. [PMID: 30387293 DOI: 10.1002/bmb.21177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/27/2018] [Accepted: 09/10/2018] [Indexed: 06/08/2023]
Abstract
Laboratory exercises focused on protein quantification are frequently conducted in traditional undergraduate biochemistry laboratory curriculum. The laboratory course described here is designed to provide students with experience in measurement of protein content in milk powder by moving reaction boundary titration (MRBT), a new rapid technique for total protein content determination in milk. In addition, this approach is weakly influenced by nonprotein nitrogen reagents such as melamine and urea. The course was done as three weekly laboratory exercises. First, students established a standard curve for milk protein concentration by MRBT method. Then, students investigated the influence of nonprotein nitrogen reagents on MRBT method. Finally, students made a comparison among three different protein quantification methods (MRBT, Biuret, and Kjeldahl method). From the experiments, students grasped the concept and advantages of MRBT and deepened the understanding of protein quantification. This course offer students the opportunity to be exposed to an advanced technique, which may have practical significance to their future study and work in the life science field. © 2018 International Union of Biochemistry and Molecular Biology, 46(6):644-651, 2018.
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Affiliation(s)
- Anling Luo
- Department of Biochemistry and Molecular Biology, School of life Sciences and Biotechnology, Shanghai Jiaotong University, Shanghai, China
| | - Youli Zheng
- Department of Biochemistry and Molecular Biology, School of life Sciences and Biotechnology, Shanghai Jiaotong University, Shanghai, China
| | - Xinxin Chen
- Department of Biochemistry and Molecular Biology, School of life Sciences and Biotechnology, Shanghai Jiaotong University, Shanghai, China
| | - Fengsong Cong
- Department of Biochemistry and Molecular Biology, School of life Sciences and Biotechnology, Shanghai Jiaotong University, Shanghai, China
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7
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Dutta D. Broadening of analyte streams due to a transverse pressure gradient in free-flow isoelectric focusing. J Chromatogr A 2017; 1484:85-92. [PMID: 28081900 PMCID: PMC5316482 DOI: 10.1016/j.chroma.2017.01.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 12/31/2016] [Accepted: 01/02/2017] [Indexed: 01/24/2023]
Abstract
Pressure-driven cross-flows can arise in free-flow isoelectric focusing systems (FFIEF) due to a non-uniform electroosmotic flow velocity along the channel width induced by the pH gradient in this direction. In addition, variations in the channel cross-section as well as unwanted differences in hydrostatic heads at the buffer/sample inlet ports can also lead to such pressure-gradients which besides altering the equilibrium position of the sample zones have a tendency to substantially broaden their widths deteriorating the separations. In this situation, a thorough assessment of stream broadening due to transverse pressure-gradients in FFIEF devices is necessary in order to establish accurate design rules for the assay. The present article describes a mathematical framework to estimate the noted zone dispersion in FFIEF separations based on the method-of-moments approach under laminar flow conditions. A closed-form expression has been derived for the spatial variance of the analyte streams at their equilibrium positions as a function of the various operating parameters governing the assay performance. This expression predicts the normalized stream variance under the chosen conditions to be determined by two dimensionless Péclet numbers evaluated based on the transverse pressure-driven and electrophoretic solute velocities in the separation chamber, respectively. Moreover, the analysis shows that while the stream width can be expected to increase with an increase in the value of the first Péclet number, the opposite trend will be followed with respect to the latter. The noted results have been validated using Monte Carlo simulations that also establish a time/length scale over which the predicted equilibrium stream width is attained in the system.
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Affiliation(s)
- Debashis Dutta
- Department of Chemistry, University of Wyoming, Laramie, WY, 82071, United States.
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8
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Zhong R, Xie H, Kong F, Zhang Q, Jahan S, Xiao H, Fan L, Cao C. Enzyme catalysis-electrophoresis titration for multiplex enzymatic assay via moving reaction boundary chip. LAB ON A CHIP 2016; 16:3538-3547. [PMID: 27464600 DOI: 10.1039/c6lc00757k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this work, we developed the concept of enzyme catalysis-electrophoresis titration (EC-ET) under ideal conditions, the theory of EC-ET for multiplex enzymatic assay (MEA), and a related method based on a moving reaction boundary (MRB) chip with a collateral channel and cell phone imaging. As a proof of principle, the model enzymes horseradish peroxidase (HRP), laccase and myeloperoxidase (MPO) were chosen for the tests of the EC-ET model. The experiments revealed that the EC-ET model could be achieved via coupling EC with ET within a MRB chip; particularly the MEA analyses of catalysis rate, maximum rate, activity, Km and Kcat could be conducted via a single run of the EC-ET chip, systemically demonstrating the validity of the EC-ET theory. Moreover, the developed method had these merits: (i) two orders of magnitude higher sensitivity than a fluorescence microplate reader, (ii) simplicity and low cost, and (iii) fairly rapid (30 min incubation, 20 s imaging) analysis, fair stability (<5.0% RSD) and accuracy, thus validating the EC-ET method. Finally, the developed EC-ET method was used for the clinical assay of MPO activity in blood samples; the values of MPO activity detected via the EC-ET chip were in agreement with those obtained by a traditional fluorescence microplate reader, indicating the applicability of the EC-ET method. The work opens a window for the development of enzymatic research, enzyme assay, immunoassay, and point-of-care testing as well as titration, one of the oldest methods of analysis, based on a simple chip.
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Affiliation(s)
- Ran Zhong
- Laboratory of Bioseparation and Analytical Biochemistry, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China. ,
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9
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Kong FZ, Yang Y, He YC, Zhang Q, Li GQ, Fan LY, Xiao H, Li S, Cao CX. Design of suitable carrier buffer for free-flow zone electrophoresis by charge-to-mass ratio and band broadening analysis. Electrophoresis 2016; 37:2393-400. [DOI: 10.1002/elps.201600040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 06/05/2016] [Accepted: 06/14/2016] [Indexed: 11/12/2022]
Affiliation(s)
- Fan-zhi Kong
- Laboratory of Analytical Biochemistry and Bio-separation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai P. R. China
| | - Ying Yang
- Laboratory of Analytical Biochemistry and Bio-separation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai P. R. China
- School of Bioscience and Bioengineering; South China University of Technology; Guangzhou P. R. China
| | - Yu-chen He
- Laboratory of Analytical Biochemistry and Bio-separation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai P. R. China
| | - Qiang Zhang
- Laboratory of Analytical Biochemistry and Bio-separation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai P. R. China
| | - Guo-qing Li
- Laboratory of Analytical Biochemistry and Bio-separation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai P. R. China
| | - Liu-yin Fan
- Laboratory of Analytical Biochemistry and Bio-separation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai P. R. China
| | - Hua Xiao
- Laboratory of Analytical Biochemistry and Bio-separation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai P. R. China
| | - Shan Li
- School of Bioscience and Bioengineering; South China University of Technology; Guangzhou P. R. China
| | - Cheng-xi Cao
- Laboratory of Analytical Biochemistry and Bio-separation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai P. R. China
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10
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Zhang LX, Cao YR, Xiao H, Liu XP, Liu SR, Meng QH, Fan LY, Cao CX. Leverage principle of retardation signal in titration of double protein via chip moving reaction boundary electrophoresis. Biosens Bioelectron 2015; 77:284-91. [PMID: 26414025 DOI: 10.1016/j.bios.2015.09.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Revised: 08/28/2015] [Accepted: 09/01/2015] [Indexed: 12/17/2022]
Abstract
In the present work we address a simple, rapid and quantitative analytical method for detection of different proteins present in biological samples. For this, we proposed the model of titration of double protein (TDP) and its relevant leverage theory relied on the retardation signal of chip moving reaction boundary electrophoresis (MRBE). The leverage principle showed that the product of the first protein content and its absolute retardation signal is equal to that of the second protein content and its absolute one. To manifest the model, we achieved theoretical self-evidence for the demonstration of the leverage principle at first. Then relevant experiments were conducted on the TDP-MRBE chip. The results revealed that (i) there was a leverage principle of retardation signal within the TDP of two pure proteins, and (ii) a lever also existed within these two complex protein samples, evidently demonstrating the validity of TDP model and leverage theory in MRBE chip. It was also showed that the proposed technique could provide a rapid and simple quantitative analysis of two protein samples in a mixture. Finally, we successfully applied the developed technique for the quantification of soymilk in adulterated infant formula. The TDP-MRBE opens up a new window for the detection of adulteration ratio of the poor food (milk) in blended high quality one.
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Affiliation(s)
- Liu-Xia Zhang
- Laboratory of Analytical Biochemistry and Bioseparation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yi-Ren Cao
- Laboratory of Analytical Biochemistry and Bioseparation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hua Xiao
- Laboratory of Analytical Biochemistry and Bioseparation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiao-Ping Liu
- Laboratory of Analytical Biochemistry and Bioseparation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shao-Rong Liu
- Department of Chemistry and Biochemistry, Oklahoma University, Norman, OK 73019, USA
| | - Qing-Hua Meng
- School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Liu-Yin Fan
- Laboratory of Analytical Biochemistry and Bioseparation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; Department of Chemistry and Biochemistry, Oklahoma University, Norman, OK 73019, USA.
| | - Cheng-Xi Cao
- Laboratory of Analytical Biochemistry and Bioseparation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
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11
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Naydenov CL, Kirazov EP, Mitev VI. Generalized Physicochemical Model for the Natural pH Gradient in Classic IEF. Chromatographia 2014. [DOI: 10.1007/s10337-014-2644-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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12
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Kitagawa F, Otsuka K. Recent applications of on-line sample preconcentration techniques in capillary electrophoresis. J Chromatogr A 2014; 1335:43-60. [DOI: 10.1016/j.chroma.2013.10.066] [Citation(s) in RCA: 137] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 10/18/2013] [Accepted: 10/21/2013] [Indexed: 12/21/2022]
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13
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Wang H, Shi Y, Yan J, Dong J, Li S, Xiao H, Xie H, Fan LY, Cao CX. Retardation Signal for Fluorescent Determination of Total Protein Content via Rapid and Sensitive Chip Moving Reaction Boundary Electrophoretic Titration. Anal Chem 2014; 86:2888-94. [DOI: 10.1021/ac403963f] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Houyu Wang
- Laboratory of
Bioseparation and Analytical Biochemistry, State Key Laboratory of
Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yongting Shi
- Laboratory of
Bioseparation and Analytical Biochemistry, State Key Laboratory of
Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jian Yan
- Institute of Refrigeration
and Cryogenics, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jingyu Dong
- School
of Chemistry and Molecule Engineering, East China University of Science and Technology, Shanghai 200234, China
| | - Si Li
- Laboratory of
Bioseparation and Analytical Biochemistry, State Key Laboratory of
Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hua Xiao
- Laboratory of
Bioseparation and Analytical Biochemistry, State Key Laboratory of
Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
- School
of Chemistry and Chemical Engieering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Haiyang Xie
- Laboratory of
Bioseparation and Analytical Biochemistry, State Key Laboratory of
Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
- School
of Chemistry and Chemical Engieering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Liu-Yin Fan
- Laboratory of
Bioseparation and Analytical Biochemistry, State Key Laboratory of
Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
- School
of Chemistry and Chemical Engieering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Cheng-Xi Cao
- Laboratory of
Bioseparation and Analytical Biochemistry, State Key Laboratory of
Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
- School
of Chemistry and Chemical Engieering, Shanghai Jiao Tong University, Shanghai 200240, China
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14
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FAN Y, LI S, FAN L, CAO C. Trace analysis of heavy metal ions in electroplate waste water by capillary electrophoresis with visual offline sample stacking via moving neutralization boundary. Se Pu 2013; 30:827-31. [DOI: 10.3724/sp.j.1123.2012.04003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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15
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Zhang W, Guo CG, Fan LY, Cao CX. Theoretical and experimental studies on isotachophoresis in multi-moving chelation boundary system formed with metal ions and EDTA. Analyst 2013; 138:5039-51. [PMID: 23806973 DOI: 10.1039/c3an00643c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this paper, a general mode and theory of moving chelation boundary based isotachophoresis (MCB-based ITP), together with the concept of decisive metal ion (DMI) having the maximum complexation constant (lg Kmax) with the chelator, were developed from a multi-MCB (mMCB) system. The theoretical deductions were: (i) the reaction boundary velocities in the mMCB system at steady state were equal to each other, resulting in a novel MCB-based ITP separation of metal ions; (ii) the boundary directions and velocities in the system were controlled by the fluxes of chelator and DMI, rather than other metal ions; and (iii) a controllable stacking of metal ions could be simultaneously achieved in the developed system. To demonstrate the deductions, a series of experiments were conducted by using model chelator of EDTA and metal ions of Cu(II) and Co(II) due to characteristic colors of blue [Cu-EDTA](2-) and pink [Co-EDTA](2-) complexes. The experiments demonstrated the correctness of theoretical deductions, indicating the validity of the developed model and theory of ITP. These findings provide guidance for the development of MRB-based ITP separation and stacking of metal ions in biological sample matrix and heavy metal ions in environmental samples.
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Affiliation(s)
- Wei Zhang
- Laboratory of Bioseparation and Analytical Biochemistry, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
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16
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Guo CG, Li S, Wang HY, Zhang D, Li GQ, Zhang J, Fan LY, Cao CX. Study on stability mechanism of immobilized pH gradient in isoelectric focusing via the Svensson–Tiselius differential equation and moving reaction boundary. Talanta 2013; 111:20-7. [DOI: 10.1016/j.talanta.2013.03.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Revised: 03/07/2013] [Accepted: 03/10/2013] [Indexed: 01/05/2023]
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17
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Guo CY, Wang HY, Liu XP, Fan LY, Zhang L, Cao CX. Fast and selective determination of total protein in milk powder via titration of moving reaction boundary electrophoresis. Electrophoresis 2013; 34:1343-51. [DOI: 10.1002/elps.201300007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 02/18/2013] [Accepted: 02/18/2013] [Indexed: 11/07/2022]
Affiliation(s)
| | - Hou-yu Wang
- Laboratory of Bioseparation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism; School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; China
| | - Xiao-Ping Liu
- Laboratory of Bioseparation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism; School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; China
| | - Liu-yin Fan
- Laboratory of Bioseparation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism; School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; China
| | - Lei Zhang
- School of Environment and Chemistry; Shanghai Normal University; Shanghai; China
| | - Cheng-xi Cao
- Laboratory of Bioseparation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism; School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; China
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18
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A visual detection of protein content based on titration of moving reaction boundary electrophoresis. Anal Chim Acta 2013; 774:92-9. [DOI: 10.1016/j.aca.2013.03.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 02/20/2013] [Accepted: 03/03/2013] [Indexed: 11/21/2022]
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19
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Wang HY, Li S, Tang YY, Dong JY, Fan LY, Cao CX. Determination of free acidic and alkaline residues of protein via moving reaction boundary titration in microdevice electrophoresis. Analyst 2013; 138:3544-51. [DOI: 10.1039/c3an36494a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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20
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Online sample pre-concentration via dynamic pH junction in capillary and microchip electrophoresis. J Sep Sci 2011; 34:2800-21. [DOI: 10.1002/jssc.201100414] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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21
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Cao C, Zhang W, Fan L, Shao J, Li S. Comparative study on sample stacking by moving reaction boundary formed with weak acid and weak or strong alkali in capillary electrophoresis. Talanta 2011; 84:651-8. [DOI: 10.1016/j.talanta.2011.01.059] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Revised: 01/14/2011] [Accepted: 01/21/2011] [Indexed: 10/18/2022]
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Liang H, OuYang LF, Liu Q, Zhang L, Tian LJ, Chen Y. Time-varying migration process of moving neutralization boundary on the immobilized pH gradient strip in the weak-base rehydration buffer. J Sep Sci 2011; 34:1212-9. [DOI: 10.1002/jssc.201000813] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 02/08/2011] [Accepted: 02/25/2011] [Indexed: 11/05/2022]
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Yang Q, Fan LY, Huang SS, Zhang W, Cao CX. Equivalence-point electromigration acid-base titration via moving neutralization boundary electrophoresis. Electrophoresis 2011; 32:1015-24. [DOI: 10.1002/elps.201000415] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 11/19/2010] [Accepted: 11/19/2010] [Indexed: 11/08/2022]
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25
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Naydenov CL, Kirazov EP, Lozanov VS, Kirazov LP, Mitev VI. Novel Methods for Controlling the Current During Isoelectric Focusing. Chromatographia 2010. [DOI: 10.1365/s10337-010-1662-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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26
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Shao J, Li S, Zhang W, Fan LY, Cao CX, Sun R, Dong YC. Controlling of band width, resolution and sample loading by injection system in a simple preparative free-flow electrophoresis with gratis gravity. J Chromatogr A 2010; 1217:2182-6. [DOI: 10.1016/j.chroma.2010.01.085] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Revised: 01/26/2010] [Accepted: 01/29/2010] [Indexed: 11/25/2022]
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Zhang W, Chen JF, Fan LY, Cao CX, Ren JC, Li S, Shao J. A novel isotachophoresis of cobalt and copper complexes by metal ion substitution reaction in a continuous moving chelation boundary. Analyst 2010; 135:140-8. [DOI: 10.1039/b912799b] [Citation(s) in RCA: 15] [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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Liang H, Chen Y, Tian LJ, Zhang L. Recursion approach for moving neutralization boundary formed on IPG strips Part I: With strong alkali rehydration buffer. Electrophoresis 2009; 30:3134-43. [DOI: 10.1002/elps.200900087] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Zhang W, Jin J, Fan LY, Li S, Shao J, Cao CX. Theoretical and experimental investigations on relationship between Kohlrausch regulating function/inequality and moving reaction boundary in electrophoresis. J Sep Sci 2009; 32:2123-31. [DOI: 10.1002/jssc.200800765] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Naydenov CL, Kirazov EP, Lozanov VS, Kirazov LP, Mitev VI. Electrochemical Reactions During Isoelectric Focusing and Their Role in Establishment of the pH Gradient. Chromatographia 2009. [DOI: 10.1365/s10337-008-0949-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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31
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Moving reaction boundary and isoelectric focusing: IV. Systemic study on Hjertén's pH gradient mobilization. J Sep Sci 2009; 32:585-96. [DOI: 10.1002/jssc.200800500] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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32
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Fan L, Li C, Zhang W, Cao C, Zhou P, Deng Z. Quantitative investigations on moving chelation boundary within a continuous EDTA-based sample sweeping system in capillary electrophoresis. Electrophoresis 2008; 29:3989-98. [DOI: 10.1002/elps.200800051] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Cao CX, Fan LY, Zhang W. Review on the theory of moving reaction boundary, electromigration reaction methods and applications in isoelectric focusing and sample pre-concentration. Analyst 2008; 133:1139-57. [DOI: 10.1039/b807450j] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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34
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Procházková B, Šalplachta J. The Use of Carrier Ampholyte-Free Isoelectric Focusing for Proteomic Analysis. Chromatographia 2007. [DOI: 10.1365/s10337-007-0463-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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35
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Procházková B, Glovinová E, Pospíchal J. Analysis of amino acids by combination of carrier ampholyte-free IEF with ITP. Electrophoresis 2007; 28:2168-73. [PMID: 17538925 DOI: 10.1002/elps.200600762] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The use of carrier ampholyte-free IEF (CAF-IEF) with ITP mobilization and conductivity detection in ITP mode for preconcentration and analysis of amino acids is demonstrated. The analytical procedure consists of three subsequent steps. In the first step, amino acids are continuously dosed from an infinite volume reservoir by electromigration to the column, where a sharp, stationary neutralization reaction boundary (NRB) is created in between acidic and basic primary electrolyte. Here, amino acids are selectively focused (trapped), if their pI falls to the pH difference on both sides of the NRB (pH gap). Amino acids create sharp rectangular zones, arranged according to their pI values. In the second step, focused zones are mobilized. After accumulation of the detectable amount of amino acids, dosing electrolyte in the infinite volume reservoir is changed for the mobilizing electrolyte. The migration mode is changed from CAF-IEF to ITP and substances start to migrate toward the analytical capillary. In the third step, analytes are transferred into the analytical column equipped with a conductivity detector and are detected in the new leading electrolyte in an ITP migration mode. The presented CAF-IEF-ITP-ITP with time-dependent accumulation of the large-volume sample enables to achieve in a reasonable time a 100 times lower c-LOD (here in orders of nmol/L), than can be reached by conventional hyphenated ITP-ITP.
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Affiliation(s)
- Barbora Procházková
- Department of Chemistry and Biochemistry, Mendel University of Agriculture and Forestry in Brno, Brno, Czech Republic
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Wang X, Zhang W, Fan LY, Hao B, Ma AN, Cao CX, Wang YX. Sensitive quantitative determination of oxymatrine and matrine in rat plasma by capillary electrophoresis with stacking induced by moving reaction boundary. Anal Chim Acta 2007; 594:290-6. [PMID: 17586127 DOI: 10.1016/j.aca.2007.05.024] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2006] [Revised: 05/15/2007] [Accepted: 05/15/2007] [Indexed: 10/23/2022]
Abstract
A quantitative method of capillary electrophoresis with sample stacking induced by moving reaction boundary (MRB) was developed for sensitive determination of oxymatrine (OMT) and matrine (MT) in rat plasma. The experimental conditions were optimized firstly. Below are the optimized experimental conditions: 20 mM sodium formate solution (HCOONa, adjusted to pH 10.70 by ammonia) as sample solution, 3 min 14 mbar sample injection, 40 mM formic buffer (HCOOH-HCOONa, pH 2.60) as stacking buffer, 7 min 14 mbar injection of stacking buffer, 100 mM HCOOH-HCOONa (pH 4.80) as separation buffer, 73 cm capillary (effective length 64 cm), 21 kV voltage, 210 nm wavelength. Under the optimized conditions, higher than 60-fold sensitivity improvement of the stacking was simply achieved as compared with capillary zone electrophoresis, and the detectable limits obtained for OMT and MT were 0.26 and 0.19 microg mL(-1), respectively. Then, numerous demonstrations were carefully performed for the methodological validations of OMT and MT in rate plasma, including high specificity of method, good linearity (r=0.9993 for OMT, r=0.9991 for MT), fair wide linear concentration range (1.30-65.00 microg mL(-1) for OMT, 0.84-42.00 microg mL(-1) for MT), low limit of detection (1.03 microg mL(-1) for OMT, 0.38 microg mL(-1) for MT), less than 5% intra- and inter-day variance value, and higher than 96% recovery of OMT and MT in plasma. The developed method could be used for the trace analyses of OMT and MT in plasma and was finally used for the investigation on pharmacokinetic study of OMT in rat plasma.
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Affiliation(s)
- Xing Wang
- Laboratory of Analytical Biochemistry & Bio-separation, Key Laboratory of Microbiology of Educational Ministry, School of Life Science and Biotechnology, Shanghai 200240, China
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Breadmore MC. Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips. Electrophoresis 2007; 28:254-81. [PMID: 17149782 DOI: 10.1002/elps.200600463] [Citation(s) in RCA: 160] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Poor sensitivity is considered to be one of the major limitations of electrophoretic separation methods, particularly when compared to traditional liquid chromatographic techniques. To address this issue, various in-line preconcentration techniques have been developed over the past 15 years, ranging in power and complexity, and there are now a number of well understood approaches routinely capable of providing a 10,000- to 100,000-fold increase in sensitivity, as well as several that can be pushed above a million. Furthermore, these have been achieved with particularly troublesome and often difficult samples, such as those having high salinity from a biological or environmental origin. This review will discuss the most common methods for improving the sensitivity of CE, CEC and microchip version of these, with particular attention to those approaches developed over the last five years.
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Affiliation(s)
- Michael C Breadmore
- Australian Centre for Research on Separation Science, School of Chemistry, University of Tasmania, Hobart, Tasmania, Australia.
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Wang QL, Fan LY, Zhang W, Cao CX. Sensitive analysis of two barbiturates in human urine by capillary electrophoresis with sample stacking induced by moving reaction boundary. Anal Chim Acta 2006; 580:200-5. [PMID: 17723774 DOI: 10.1016/j.aca.2006.07.073] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2006] [Revised: 07/26/2006] [Accepted: 07/27/2006] [Indexed: 02/05/2023]
Abstract
An on-line stacking method based on moving reaction boundary (MRB) was developed for the sensitive determination of barbital and phenobarbital in human urine via capillary electrophoresis (CE). The optimized conditions for the method are: 60 mmol L(-1) pH 11.0 Gly-NaOH as the background electrolyte, 10 mmol L(-1) pH 5.5 Gly-HCl as sample buffer, secobarbital as the internal standard (IS), 12.5 kV, 1.4 psi 10s sample injection, 75 microm ID 60.2 cm total length (50 cm effective length) capillary and 214 nm detect wavelength. Under the optimized conditions, the method can well stack and separate barbital and phenobarbital in urine samples and result in 20.5-fold and 22.6-fold improvement in concentration sensitivity for barbital and phenobarbital, respectively. Furthermore, the method holds: (1) good linear calibration functions for the two target compounds (correlation coefficients r>0.999), (2) low limits of detection (0.27 microg mL(-1) for barbital and 0.26 microg mL(-1) for phenobarbital), (3) low limits of quantification (0.92 microg mL(-1) for barbital and 0.87 microg mL(-1) for phenobarbital), (4) good precision (R.S.D. of intra-day and inter-day less than 5.38% for barbital and 1.67% for phenobarbital, respectively) and (5) high recoveries at three concentration levels (90.27-106.36% for barbital and 93.05-113.60% for phenobarbital in urine). The method is simple, sensitive and efficient, and can fit to the need of clinical and forensic toxicology.
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Affiliation(s)
- Qiu-Ling Wang
- Laboratory of Analytical Biochemistry & Bioseparation, School of Life Science & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
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Qin WH, Cao CX, Li S, Zhang W, Liu W. Quantitative study on selective stacking of zwitterions in large-volume sample matrix by moving reaction boundary in capillary electrophoresis. Electrophoresis 2005; 26:3113-24. [PMID: 16041697 DOI: 10.1002/elps.200400010] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The paper advanced the theoretical procedures for quantitative design on selective stacking of zwitterions in full capillary sample matrix by a cathodic-direction moving reaction boundary (MRB) in capillary electrophoresis (CE) under control of electroosmotic flow (EOF). With the procedures, we conducted the theoretical computations on the selective stacking of two test analytes of L-histidine (His) and L-tryptophan (Trp) by the MRB created with 30 mM pH 3.0 formic acid-NaOH buffer and 2-80 mM sodium formate. The results revealed the following three predictions. At first, the MRB cannot stack His and Trp plugs if less than 12.5 mM sodium formate is used to form the MRB and prepare the sample matrix. Second, the MRB can stack His and/or Trp sample plugs completely if higher than 50 mM sodium formate is chosen to form the MRB. Third, the MRB can only focus His plug completely, but stack Trp plug partially if 20-50 mM sodium formate is used; this implied the complete MRB-induced selective stacking to His rather than Trp. All the three predictions were quantitatively proved by the experiments. With great dilution of sample matrix and control of EOF, controllable, simultaneous and MRB-induced selective stacking and separation of zwitterions were achieved. The theoretical results hold evident significances to the quantitative design of selective stacking conditions and the increase of detection sensitivity of zwitterions in CE. In addition, the control of EOF by cetyltrimethylammonium bromide (CTAB) can evidently improve the stacking efficiency to both His and Trp.
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Affiliation(s)
- Wei-Hua Qin
- Laboratory of Analytical Biochemistry & Bioseparation, School of Life Science and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang, 200240 Shanghai, China
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Li S, Cao CX, Lin ZX, Luo JF. Theoretical study on colloid/or inorganic material preparation by moving reaction boundary method in gel. Colloid Polym Sci 2005. [DOI: 10.1007/s00396-004-1263-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Cao CX, Zhou SL, Qian YT, He YZ, Wang CR, Zheng XY, Chen WK. Investigations on factors that influence the moving neutralization reaction boundary method for capillary electrophoresis and isoelectric focusing. J Chromatogr A 2002; 952:29-38. [PMID: 12064542 DOI: 10.1016/s0021-9673(02)00063-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We investigated several factors, such as temperature, current intensity (i), time (t) and the product (mA min mm(-2), viz., C mm(-2)) of i and t, etc., that obviously affect the moving neutralization reaction boundary method (MNRBM). The results manifest that the temperature and the product ti have a strong influence on the movement rate of the boundary. The data prove that about 0.6 C mm(-2) (being equivalent to 10 mA min mm(-2)) is a critical point. If the product ti is lower than the critical point, a good quantitative agreement exists between the observed and theoretical values, but if it is higher than the critical point, the agreements are poor. The optimized experimental conditions are: (1) 18-20 degrees C room temperature, (2) 0.6-0.8 mA mm(-2), (3) less than 10 mA min mm(-2), (4) 1% agarose gel, (5) daily prepared solution and gel containing NaOH. The optimized MNRBM is of benefit for the studies on MNRB itself, isoelectric focusing and capillary zone electrophoresis as will be partially shown in this paper.
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Affiliation(s)
- Cheng-Xi Cao
- College of Life Science and Biotechnology, Shanghai Jiaotong University, China.
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Cao CX, He YZ, Li M, Qian YT, Yang L, Qu QS, Zhou SL, Chen WK. Improving separation efficiency of capillary zone electrophoresis of tryptophan and phenylalanine with the transient moving chemical reaction boundary method. J Chromatogr A 2002; 952:39-46. [PMID: 12064544 DOI: 10.1016/s0021-9673(02)00065-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
A simple and convenient mode--moving chemical reaction boundary method-capillary zone electrophoresis (MCRBM-CZE)--was designed for the enhancement of separating efficiency of CZE. In this mode, the transient MCRBM is used for the on-line pre-treatment of sample. By analyses of tryptophan (Trp) and phenylalanine (Phe) as an example, the experiments by MCRBM-CZE were carried out and further compared with those by normal CZE without the transient MCRBM. The results reveal that by carefully selected appropriate electrolytes, a strong condensation effect can be achieved by using MCRBM-CZE; this effect can greatly improve the separation efficiency, resolution and peak height of Trp and Phe in CZE as compared with those of normal CZE of Trp and Phe. Even if the sample comprises high concentrations of salt, such as 80 mM NaCl (concentration of sodium ion up to 145.6 mM), the same condensation effect can also been observed; this implies obvious significance for biological samples like urine and serum. However, if the electrolytes was chosen inappropriately only a poor compression effect of sample was observed in the MCRBM-CZE runs.
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Affiliation(s)
- Cheng-Xi Cao
- College of Life Science and Biotechnology, Shanghai Jiaotong University, China.
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Cao CX, Zhou SL, Qian YA, He YZ, Yang L, Qu QS, Chen WK. Experimental investigation on moving chemical reaction boundary theory for weak-acid-strong-base system with background electrolyte KCl in large concentration. J Chromatogr A 2001; 922:283-92. [PMID: 11486874 DOI: 10.1016/s0021-9673(01)00847-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In this report, the moving chemical reaction boundary (MCRB) was formed with the weak acid of acetic acid (HAc) and the strong alkali of NaOH, coupled with the excess of background electrolyte KCl. The experiments were compared with the predictions by the moving chemical reaction boundary equation (MCRBE). It is very interesting that (1) the experimental results are in good agreement with the predictions with the original MCRBE if the MCRB is an anodic moving boundary, (2) however, the experiments are extremely far away from the predictions with the original MCRBE if a cathodic moving boundary. Hence, the original MCRBE must be corrected under the later situation of cathodic moving MCRB. The corrected MCRBE was well quantitatively proved to be valid for the cathodic moving MNRB formed with the same electrolytes of HAc, NaOH and KCl.
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Affiliation(s)
- C X Cao
- Department of Chemistry, University of Science and Technology of China, Hefei.
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Abstract
The applicability of carrier ampholyte-free isoelectric focusing (CAF-IEF) for analyses of ampholytes is demonstrated. The suggested method is based on the principle of both side regulated ionic matrix in CAF-IEF. A sharp step of pH is created in the column filled with a sample dissolved in a background electrolyte by influence of current and solvolytic fluxes. Here, ampholytes are focused upon. The magnitude of the step, its velocity and direction of its movement can be regulated electrically. In this manner, favorable separation properties of the system can be set up, even during the run. This brings several advantages over conventional methods. The principles of the separation can be easily changed, permitting selective pre-concentration (trapping) of minor components by processing large amounts of a sample to be preformed, effective isotachophoresis or IEF pre-separation and final electrophoretic analysis in one run. Advantages of these combinations are discussed together with the right choice of the working electrolyte. A 1000-fold increase in amount of substance in a column can be achieved for both isotachophoresis and capillary zone electrophoresis combined with CAF-IEF pre-concentration at reasonable working conditions. It enables a limit of detection at the nmol/l level with a concentration factor of about 10(7) to be reached.
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Affiliation(s)
- J Pospíchal
- Department of Chemistry and Biochemistry, Mendel University of Agriculture and Forestry in Brno, Czech Republic
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Cao CX, Li RZ, Zhuo SL, Chen WK, Qian YT. Stable colloid of Co(OH)2 prepared by moving chemical reaction boundary method (MCRBM) in agarose gel. Colloids Surf A Physicochem Eng Asp 2001. [DOI: 10.1016/s0927-7757(00)00740-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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46
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Cao CX, Zhou SL, He YZ, Qian YT, Yang L, Qu QS, Gan WE, Dong L, Zhao YQ, Chen WK. Corrections to moving chemical reaction boundary equation for weak reactive electrolytes under the existence of background electrolyte KCl in large concentrations. J Chromatogr A 2001; 907:347-52. [PMID: 11217043 DOI: 10.1016/s0021-9673(00)01075-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this report, the moving chemical reaction boundary (MCRB) was formed by the weak reaction electrolytes of NH3.H2O and CH3COOH under the existence of background electrolyte KCl in large concentrations, the experiments were compared with the predictions by the moving chemical reaction boundary equation (MCRBE) for weak reactive electrolytes. It was found that the experimental results are far from the predictions with the MCRBE. So the MCRBEs must be corrected under the given experimental conditions. The corrected MCRBEs are given for the MCRB formed with weak reactive electrolytes coupled with KCl at high concentrations.
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Affiliation(s)
- C X Cao
- Department of Chemistry, University of Science and Technology of China, Hefei.
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Cao CX, Zhou SL, You-Zhao H, Zheng XY, Chen WK, Qian YA. Experimental study on moving neutralization reaction boundary created with the strong reactive electrolytes of HCl and NaOH in agarose gel. J Chromatogr A 2000; 891:337-47. [PMID: 11043794 DOI: 10.1016/s0021-9673(00)00653-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In this paper, a moving neutralization reaction boundary (MNRB) is created with the strong reactive electrolytes of HCl and NaOH in agarose gel. The motions of the MNRB are investigated and compared with the predictions with the theory of the moving chemical reaction boundary (MCRB). The results show that, under appreciate experimental conditions, the experiments on the MNRB are exactly in coincidence with the predictions with the MCRB theory. Thus, the results excellently demonstrate that the MCRB theory is valid for the MNRB formed with the strong reactive electrolytes of HCl and NaOH. Additionally, it is, as discussed in this paper, imperative to develop a method to obtain ionic mobility at different temperatures and ionic strengths, in order to investigate the movements of the MCRB more efficiently.
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Affiliation(s)
- C X Cao
- Department of Chemistry, University of Science and Technology of China, Hefei.
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Cao CX, Zheng QS, Chen WK, Zhu JH. The unvalidity of Kohlrausch' regulating function for Svensson's isoelectric focusing and stationary electrolysis at steady state. J Chromatogr A 1999; 863:219-26. [PMID: 10593501 DOI: 10.1016/s0021-9673(99)00912-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Kohlrausch' regulating function is of important significance in the field of electrophoresis. In this paper, the relative regulating function is defined from Kohlrausch' regulating function. The relative values, including the limited values, of the regulating function for the stationary electrolysis of salt, on which the classic isoelectric focusing (IEF) is based, are computed and compared with the computer program of the QBASIC written by us. The results directly demonstrate that, (1) in a few cases the regulating function is valid for the stationary electrolysis and IEF, whereas (2) the function is, in most of cases, not valid for the stationary electrolysis and IEF at steady-state. Those findings may be useful for the studies on the relationships between Kohlrausch' regulating function and IEF and for the classification of numerous electrophoretic techniques.
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Affiliation(s)
- C X Cao
- Department of Chemistry, University of Science and Technology of China, Anhui Hefei.
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