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Novel approach for the synthesis of a neutral and covalently bound capillary coating for capillary electrophoresis-mass spectrometry made from highly polar and pH-persistent N-acryloylamido ethoxyethanol. Anal Bioanal Chem 2019; 412:561-575. [PMID: 31872272 DOI: 10.1007/s00216-019-02286-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 10/28/2019] [Accepted: 11/14/2019] [Indexed: 10/25/2022]
Abstract
Statically adsorbed or covalently coupled capillary coatings are of crucial importance in capillary electrophoresis-mass spectrometry for the separation of peptides and proteins. So far, published coating strategies and commercially available coated capillaries have a limited pH-stability so that the analysis at strongly acidic pH is limited, or harsh rinsing procedures for biological sample analysis cannot be applied. We here present a capillary coating based on Si-C linkages to N-acryloylamido ethoxyethanol (AAEE) with a new synthetic strategy including LiAlH4 surface reaction. We optimized the coating method with emphasis on stability and reproducibility applying harsh rinsing procedures (strong acid, strong base and organic solvent), using the electroosmotic mobility and separation efficiency of tryptic peptides as performance measure. Complete synthesis is performed in less than 2 days for up to 8 capillaries in parallel of more than 16 m total length. Intra- and inter-batch reproducibility were determined regarding electroosmotic mobility, separation efficiency and migration time precision in CE-MS separations of tryptically digested bovine serum albumin. Coating stability towards rinsing with strong acid (1 mol/L HCl), organic solvent (acetonitrile) and strong base (1 mol/L NaOH) was investigated. Outstanding performance was found for single capillaries. However, inter-capillary reproducibility is discussed critically. The new coating was successfully applied for reproducible CE-MS separation of large proteins in diluted serum, medium-sized peptides and small and highly charged polyamines in fish egg extracts using a very acidic background electrolyte containing 0.75 mol/L acetic acid and 0.25 mol/L formic acid (pH 2.2).
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2
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Abstract
This review article describes the preparation of dynamic and static polymeric wall coatings for capillary electrophoresis. Properties of bare fused-silica surfaces and methods for the characterization of capillary coatings are summarized. The preparation and basic properties of neutral and charged wall coatings are considered. Finally, advantages and potential applications of various coatings are discussed.
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Affiliation(s)
- J Horvath
- Molecular Dynamics Inc., Sunnyvale, CA 94085, USA.
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3
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Kim JB, Otsuka K, Terabe S. On-line sample concentration in micellar electrokinetic chromatography with cationic micelles in a coated capillary. J Chromatogr A 2001; 912:343-52. [PMID: 11330804 DOI: 10.1016/s0021-9673(01)00599-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electroosmotic flow was successfully suppressed even in the presence of cationic surfactants, when a polyacrylamide-coated capillary was employed. Two on-line sample concentration techniques of sample stacking and sweeping were evaluated in micellar electrokinetic chromatography (MEKC) using the polyacrylamide-coated capillary. Cationic surfactants were used as pseudostationary phases in MEKC. At least 60-fold and about 600-fold increases in detection sensitivity were obtained in terms of peak heights by sample stacking and sweeping, respectively.
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Affiliation(s)
- J B Kim
- Faculty of Science, Himeji Institute of Technology, Kamigori, Hyogo, Japan.
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4
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Abstract
We have developed a microfabricated analytical device on a glass chip that performs a protein sizing assay, by integrating the required separation, staining, virtual destaining, and detection steps. To obtain a universal noncovalent fluorescent labeling method, we have combined on-chip dye staining with a novel electrophoretic dilution step. Denatured protein-sodium dodecyl sulfate (SDS) complexes are loaded on a chip and bind a fluorescent dye as the separation begins. At the end of the separation channel, an intersection is used to dilute the SDS below its critical micelle concentration before the detection point. This strongly reduces the background due to dye molecules bound to SDS micelles and also increases the peak amplitude by 1 order of magnitude. Both the on-chip staining and SDS dilution steps occur in the 100-ms time scale and are approximately 10(4) times faster than their conventional counterparts in SDS-PAGE. This represents a much greater speed increase due to microfabrication than has been obtained in other assay steps such as electrophoretic separations. We have designed and tested a microchip capable of sequentially analyzing 11 different samples, with sizing accuracy better than 5% and high sensitivity (30 nM for carbonic anhydrase).
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Affiliation(s)
- L Bousse
- Caliper Technologies Corp., Mountain View, California 94043-2234, USA.
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6
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Takeda S, Tanaka Y, Nishimura Y, Yamane M, Siroma Z, Wakida S. Analysis of dyestuff degradation products by capillary electrophoresis. J Chromatogr A 1999; 853:503-9. [PMID: 10486759 DOI: 10.1016/s0021-9673(99)00579-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Capillary electrophoresis (CE) with two different detection methods, mass spectrometry (MS) and UV absorption spectroscopy with photodiode array detection (UV/DAD), was used for the analysis of the degradation products of dyestuffs. We have studied wet oxidation with solid catalyst as the treatment method of wastewaters containing dyestuffs. When the Orange II (C.I. Acid Orange 7) solution was used as the model wastewater, treated solution contained unknown highly polar degradation products. We were able to determine the molecular masses of some products by CE-MS. From this clue, we tried to identify these products by CE-UV/DAD. By means of the comparison of the migration time and UV spectra of standard samples, three degradation products were identified. The separation of degradation products was successful within 15 min.
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Affiliation(s)
- S Takeda
- Department of Energy and the Environment, Osaka National Research Institute, AIST, Japan
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7
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Separation of acidic enantiomers by capillary electrophoresis–mass spectrometry employing a partial filling technique. J Chromatogr A 1998. [DOI: 10.1016/s0021-9673(97)01073-x] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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8
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TANAKA Y, KISHIMOTO Y, TERABE S. Analysis of Charged Cyclodextrin Derivatives by On-Line Capillary Electrophoresis-Ionspray-Mass Spectrometry. ANAL SCI 1998. [DOI: 10.2116/analsci.14.383] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Yoshihide TANAKA
- Department of Analytical Chemistry, Nippon Boehringer Ingelheim Co. Ltd
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9
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Klyushnichenko V, Tishkov V, Kula MR. Rapid SDS-Gel capillary electrophoresis for the analysis of recombinant NADP(+)-dependent formate dehydrogenase during expression in Escherichia coli cells and its purification. J Biotechnol 1997; 58:187-95. [PMID: 9470223 DOI: 10.1016/s0168-1656(97)00149-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The level of expression in Escherichia coli cells and different steps of purification of the recombinant NADP(+)-dependent formate dehydrogenase (EC 1.2.1.2, FDH) from bacterium Pseudomonas sp.101 was analyzed by rapid SDS-Gel capillary electrophoresis (SDS-Gel CE) and compared with SDS polyacrylamide gel electrophoresis (SDS PAGE). First standard proteins were separated in the short capillary and the calibration curve generated, then fractions taken during the fermentation and purification process were analysed. The main advantages of SDS-Gel CE are short analysis time, high sensitivity, the possibility to quantify proteins at different ultraviolet wavelength, and small injection volumes. The data for each step of the fermentation process and during the purification were controlled by spectrophotometric analysis of enzyme activity and protein concentration as well as standard SDS PAGE. The molecular mass of the purified FDH was determined as 44,078 Da by matrix-assisted laser desorption/ ionisation time of flight mass spectrometry.
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Affiliation(s)
- V Klyushnichenko
- Institute of Enzyme Technology, Heinrich-Heine University Düsseldorf.
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10
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Haginaka J, Kanasugi N. Separation of basic drug enantiomers by capillary zone electrophoresis using ovoglycoprotein as a chiral selector. J Chromatogr A 1997. [DOI: 10.1016/s0021-9673(97)00519-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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11
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Klyushnichenko V, Kula MR. Sodium dodecyl sulfate-polymer capillary electrophoresis for the analysis of cell culture proteins. Electrophoresis 1997; 18:2019-23. [PMID: 9420162 DOI: 10.1002/elps.1150181123] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The application of sodium dodecyl sulfate (SDS)-polymer capillary electrophoresis (CE) to the analysis of proteins of hybridoma cell culture supernatant is demonstrated. All steps of the developed analysis are shown and discussed. Following optimization of sample preparation and concentration, as well as of the mode of injection all main protein components were separated with high resolution and selectivity. Proteolytic degradation of IgG, due to microbial contamination, was observed on SDS-gel CE and capillary zone electrophoresis (CZE). The technique was applied to monitor the cell cultivation process and concentrations of main components are demonstrated. IgG was found to increase from initially 5 mg/L to 20 mg/L after 4 days and to > 130 mg/L after 14 days of cultivation. The techniques may be applied to other biotechnological processes for the production or purification of proteins.
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Affiliation(s)
- V Klyushnichenko
- Institute of Enzymetechnology, Heinrich-Heine University Düsseldorf, Jülich, Germany
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12
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Tanaka Y, Terabe S. Enantiomer separation of acidic racemates by capillary electrophoresis using cationic and amphoteric beta-cyclodextrins as chiral selectors. J Chromatogr A 1997; 781:151-60. [PMID: 9368383 DOI: 10.1016/s0021-9673(97)00489-5] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Enantiomer separations of various acidic racemates were performed by capillary electrophoresis (CE) using a commercial cationic beta-cyclodextrin (beta-CD), quaternary ammonium beta-CD (QA-beta-CD), and a commercial amphoteric beta-CD (AM-beta-CD) as chiral selectors. Eleven acidic racemates were successfully separated using QA-beta-CD by changing the CD concentration and the buffer pH. These enantiomer separations were compared with the results using five neutral CD derivatives. Although most racemates were separated with some of the neutral CDs, relatively high CD concentrations were required to obtain baseline separations. In contrast, when QA-beta-CD was employed, the enantiomer separations were successful at low concentrations below 5 mM. Enantiomers of five acidic racemates and ten dansylated amino acids (Dns-amino acids) were separated using AM-beta-CD. Although the baseline separation of racemic 4-chloromandelic acid was not achieved with either QA-beta-CD or five neutral CDs, AM-beta-CD showed complete resolution. Furthermore, the simultaneous enantiomer separation of eight Dns-amino acids was also achieved with AM-beta-CD. Both QA-beta-CD and AM-beta-CD were analyzed by CE and mass spectrometry (MS) in order to identify their compositions because they consisted of a mixture having different degrees of substitution. QA-beta-CD consisted of six components having from one to six quaternary ammonium groups. The composition of AM-beta-CD, however, was very complicated and could not be identified.
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Affiliation(s)
- Y Tanaka
- Department of Analytical Chemistry, Nippon Boehringer Ingelheim Co. Ltd., Hyogo, Japan
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13
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Nakatani M, Shibukawa A, Nakagawa T. Separation mechanism of pullulan solution-filled capillary electrophoresis of sodium dodecyl sulfate-proteins. Electrophoresis 1996; 17:1584-6. [PMID: 8957185 DOI: 10.1002/elps.1150171015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The separation mechanism of capillary electrophoresis of sodium dodecyl sulfate (SDS)-proteins using pullulan with a molecular mass range of 50,000-100,000 as a separation matrix was investigated. The pullulan solution was filled into fused-silica capillaries whose inner walls were coated with linear polyacrylamide through chemically stable Si-C linkages. Baseline separations of SDS proteins were achieved at concentrations ranging from 3-10% w/v of pullulan. The entanglement threshold of pullulan solution was found to be around 0.5% w/v, indicating migration of SDS-proteins through an entangled pullulan network. Ferguson plots exhibited a linear relationship between log mobility and pullulan concentration. Linear relationships were also obtained for double logarithmic plots of the electrophoretic mobility and protein molecular mass. These results show that the separation is based on mass discrimination in accordance with the Ogston theory.
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Affiliation(s)
- M Nakatani
- Pharmaceutical Research Dept., Nippon Boehringer Ingelheim Co., Ltd., Hyogo, Japan
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14
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Tanaka Y, Yanagawa M, Terabe S. Separation of neutral and basic enantiomers by cyclodextrin electrokinetic chromatography using anionic cyclodextrin derivatives as chiral pseudo-stationary phases. ACTA ACUST UNITED AC 1996. [DOI: 10.1002/jhrc.1240190802] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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15
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Nakatani M, Shibukawa A, Nakagawa T. Effect of temperature and viscosity of sieving medium on electrophoretic behavior of sodium dodecyl sulfate-proteins on capillary electrophoresis in presence of pullulan. Electrophoresis 1996; 17:1210-3. [PMID: 8855406 DOI: 10.1002/elps.1150170707] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Pullulan was used as a sieving medium in high-performance capillary gel electrophoresis to study the effect of temperature and viscosity on electrophoretic behavior of sodium dodecyl sulfate (SDS)-proteins with molecular masses in the range of 14,400-116,000 Da. The migration time decreased with increasing capillary temperature. Equations were derived relating mobility of SDS-proteins to capillary temperature and viscosity of pullulan solution. Linear relationships were obtained from experiments between logarithm of mobility and reciprocal temperature and between double logarithmic values of mobility and viscosity of pullulan solution. The experimental results agree well with the equations.
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Affiliation(s)
- M Nakatani
- Pharmaceutical Research Department, Nippon Boehringer Ingelheim Co., Ltd., Hyogo, Japan
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16
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Gump EL, Monnig CA. Pre-column derivatization of proteins to enhance detection sensitivity for sodium dodecyl sulfate non-gel sieving capillary electrophoresis. J Chromatogr A 1995. [DOI: 10.1016/0021-9673(95)00591-a] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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17
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Nakatani M, Shibukawa A, Nakagawa T. Chemical stability of polyacrylamide-coating on fused silica capillary. Electrophoresis 1995; 16:1451-6. [PMID: 8529613 DOI: 10.1002/elps.11501601240] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The chemical stability of polyacrylamide coatings on a fused silica capillary for capillary electrophoresis was investigated with respect to temperature of capillary and pH as well as salt concentration of running buffer solution by evaluating their effects on electroosmotic mobility. The capillary covalently bonded to linear polyacrylamide through Si-C linkage was stable in buffer solutions of pH 2.3-8.0 at 30 degrees C for 30 days, whereas the capillary bonded through Si-O-Si-C linkage was damaged at pH above 4.6. The electroosmotic mobility observed in both capillaries increased with increasing temperature, though the degree of increase was smaller in the Si-C linked capillary than in the Si-O-Si-C linked capillary. The increase in the buffer concentration resulted in increased electroosmotic mobility in the Si-O-Si-C linked capillary, but no effect was observed for the Si-C linked capillary.
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Affiliation(s)
- M Nakatani
- Pharmaceutical Research Department, Nippon Boehringer Ingelheim, Hyogo
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18
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Partial separation zone technique for the separation of enantiomers by affinity electrokinetic chromatography with proteins as chiral pseudo-stationary phases. J Chromatogr A 1995. [DOI: 10.1016/0021-9673(94)00790-g] [Citation(s) in RCA: 147] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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19
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Nakatani M, Shibukawa A, Nakagawa T. High-performance capillary electrophoresis of SDS-proteins using pullulan solution as separation matrix. J Chromatogr A 1994; 672:213-8. [PMID: 8069394 DOI: 10.1016/0021-9673(94)80609-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Sodium dodecyl sulphate (SDS) capillary electrophoresis using pullulan solution as a separation matrix was developed for the separation and molecular mass determination of proteins. The silanol functions on the inner surface of a fused-silica capillary were deactivated by coating with linear polyacrylamide through Si-C linkages, into which the pullulan solution was filled. The stability of the coating was examined by exposure to an alkaline buffer solution (pH 9.2) for up to 30 days. Compared with conventional coatings with linear polyacrylamide through siloxane linkages, the present capillary was more stable even under alkaline conditions and markedly reduced electroosmotic flow. Thus, polymer solutions of low viscosity such as pullulan solution could be stabilized in the capillary, resulting in a prolonged life-span of the capillary and improved reproducibility of separations. An excellent linear relationship was obtained between the mobility and the logarithm of the molecular mass of SDS-proteins. The relative standard deviation of migration times was below 0.5% when the pullulan solution was refilled in each analysis (n = 10). The calibration plots of the integrated peak areas at 214 nm vs. concentration of standard proteins were linear in the range 5 micrograms/ml-0.1 mg/ml.
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Affiliation(s)
- M Nakatani
- Pharmaceutical Research Department, Nippon Boehringer Ingelheim Co. Ltd., Hyogo, Japan
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