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  • 1
    Electronic Resource
    Electronic Resource
    Analysis of macromolecular branched chain polypeptides by capillary electrophoresis and micellar electrokinetic chromatography (1996)
    Weinheim : Wiley-Blackwell
    Electrophoresis 17 (1996), S. 1357-1360 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Micellar electrokinetic chromatography ; Macromolecular branched chain polypeptides ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Amphoteric poly(Lys-[Glu1.0-DL-Ala4.1]), (EAK) and anionic poly(Lys-Ac-Glu0.98-DL-Ala3.98]), (AcEAK) branched chain polypeptides were analyzed by capillary electrophoresis (CE) and micellar elektrokinetic chromatography (MEKC) in the following buffers. A1: 0.25 N triethyl ammonium phosphate (TEAP) buffer (pH 2.25); A2: 100 mM sodium dodecyl sulfate (SDS) in buffer A1; B1: Na-borate buffer (pH 7.7); B2: 100 mM SDS in buffer B1; C1: Na-borate buffer (pH 11.0); C2: 100 mM SDS in buffer C1. Both EAK and AcEAK could be separated by a CE mechanism at pH 2.25 and by an MEKC mechanism at pH 11.0. Optimum results were achieved with CE in buffer A1 and with MEKC in buffer C2.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150170813
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Comparative analysis of somatostatin analog peptides by capillary electrophoresis and micellar elektrokinetic chromatography (1996)
    Weinheim : Wiley-Blackwell
    Electrophoresis 17 (1996), S. 758-761 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Micellar electrokinetic chromatography ; Somatostatin analog peptides ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Capillary electrophoresis (CE) and micellar electrokinetic chromatography (MEKC) methods, utilizing uncoated silica capillary and triethyl ammonium phosphate or sodium borate buffers in the pH range of 2.25-11.0, containing sodium dodecyl sulfate (SDS) (0-100 mM) for analysis of somatostatin-analog peptides were developed. The method presented here was compared with the reversed-phase high performance liquid chromatographic (RP-HPLC) and CE methods developed for analysis of peptides. The peptides investigated in this work can be separated by CE on the basis of their electrophoretic mobility in aqueous buffer of low pH value (pH 2.25) or by MEKC on the basis of their hydrophobicity in SDS containing buffer of high pH value (pH 11.0). Optimal MEKC separation of the investigated peptides has been achieved at pH 11.0 in an Na-borate buffer containig 100 mM SDS. CE at pH 2.25 proved insensitive to the hydrophobicity of the peptides investigated. By contrast, results obtained with MEKC at pH 11.0 proved to be anologous to those obtained by RP-HPLC, with highly hydrophobic peptides - migrating slower than peptides without hydrophobic moieties.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150170422
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Calculation of modified capacity factor in micellar electrokinetic chromatography (1996)
    Weinheim : Wiley-Blackwell
    Electrophoresis 17 (1996), S. 762-765 
    Details
    ISSN: 0173-0835
    Keywords: Micellar elektrokinetic chromatography ; Modified capacity factor ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: In addition to the expression, k′ = (tm-to)/to (1-tm/tmc), we propose the expression k″ = (tm-to)/(tmc-to) to calculate the capacity factor in micellar electrokinetic chromatography (MEKC), where tm, to, and tmc are the migration time of the analyte, the flow marker, and the micelles, respectively. The k′ and k″ values that were obtained from simulated data as well as from MEKC analysis of different peptides (in 100 mM sodium dodecyl sulfate/0.1 N sodium borate buffer at pH 11.0) were calculated and compared. The k″ value is equal to zero for an analyte remaining in the aqueous phase whereas it is equal to one for an analyte always staying in the micellar phase. By applying k″ a finite capacity factor can be obtained for an analyte, indicating its partition between the two moving phases (aqueous and micellar) even in those cases when tm equals tmc. The slope of the curve k″ as a function of tm is constant through the whole migration window and therefore peak compression does not occur when applying k″ to calculate the capacity factor. A given difference in k″ corresponds the same difference in migration times and this value does not depend on the position within the migration window. Since k″ is a normalized paramete it is easy to evaluate the significance of a given difference in capacity factor or to estimate the relative position of an analyte with a given capacity factor in the migration window by applying k″. Therefore, k″ seems to be an adequate parameter to calculate the capacity factor in MEKC and, similar to k′, it also refers to the hydrophobicity of the analyte.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150170423
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Analysis of polyanionic macromolecular carrier poly-(N-vinylpyrrolidone-co-maleic acid) and its bioconjugates by capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 295-299 
    Details
    ISSN: 0173-0835
    Keywords: Capillary zone electrophoresis ; Micellar electrokinetic chromatography ; Polyanionic macromolecular carrier ; Conjugate ; Tyrosine kinase molecule ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Aninonic carrier poly(N-vinylpyrrolidone-co-maleic acid) and its conjugates, prepared with coupling of 2-cyano-3-hydroxy-5-amino-2-pentenoyc(4-trifluoromethyl anilide) or (6′,7′-dimethyl-1′-quinoxalinyl)-4-(2′ amino) acetanilide to the carrier, were analyzed by capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) in the following buffers: 0.25N triethylammonium phosphate (TEAP); sodium dodecyl sulfate (SDS; 25-150 mM) in TEAP (pH 2.25-6.30); 0.1 M Na-borate buffer (pH range 7-11) and SDS (25-150 mM) in Na-borate buffer (pH range 7-11). The presence of strong carboxyl groups (dissociated even at pH 2.25) on the polymer chain was proved by the CZE method. It was also proved by potentometric titration that carboxyls with a wide range of acidity were on the polymer chain. CZE was able to differentiate among the analytes possessing carboxyl groups of different acidic strengths at pH 2.25. These components were not distinguished by CZE at high pH va use (11.0). Interaction between the analyte and SDS affected the separation at this pH, and hence good resolution was obtained by MEKC. Informative separations were achieved both for the carrier and the conjugates in TEAP buffer at pH 2.25 by the CZE method. Optimal separation was achieved in borate buffer containign 75 mM SDS at pH 11.0 for the carrier and at pH 7.7 for the conjugates in MEKC.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190225
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    Paper (German National Licenses)
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