Poly(methylglutamate)-coated surfaces in HPLC and CE

Bentrop, D.; Kohr, Jörg; Engelhardt, H.

doi:10.1007/bf02325022

Cited by 47 publications

(15 citation statements)

References 46 publications

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“…Hjerten [25] used a neutral polymer (methylcellulose) to coat a fused silica capillary to suppress EOF. Other neutral polymers used as coating materials include poly(methylglutamate) (PMG) [26], poly(vinyl alcohol) (PVA) [27], polyethylene glycols (PEG) [28], and Ucon [29,30]. Depending on the desired direction of EOF and the properties of analytes, either positively or negatively charged coatings have been used [31 -37].…”

Section: Introductionmentioning

confidence: 99%

Negatively charged sol‐gel column with stable electroosmotic flow for online preconcentration of zwitterionic biomolecules in capillary electromigration separations

Fries

Malik³

2005

J of Separation Science

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A negatively charged sol-gel coating was developed for on-line preconcentration of zwitterionic biomolecules in capillary electrophoresis (CE), using asparagine and myoglobin as representative zwitterionic bioanalytes. The sol-gel coating was created by using a solution containing three precursors: mercaptopropyltrimethoxysilane (MPTMS), tetramethoxysilane (TMOS), and n-octadecyltriethoxysilane (C18-TEOS). The resulting sol-gel coating contained chemically bonded mercaptopropyl functional groups that were further oxidized by hydrogen peroxide to the corresponding sulfonic acid moieties. Such a surface-bonded sol-gel coating can carry a negative charge over a wide range of pH due to the presence of deprotonated sulfonic acid groups. Under favorable pH conditions, the negatively charged sol-gel coating can facilitate the extraction of positively charged analytes from a zwitterionic sample through electrostatic interaction. This principle was employed to extract myoglobin and asparagine by passing aqueous samples of these zwitterionic analytes through a negatively charged sol-gel column. The extracted analytes were then desorbed and focused via local pH change and stacking. The local pH change was accomplished by passing a buffer solution with a pH above the solute p/ value, while a dynamic pH junction between the sample solution and the background electrolyte was utilized to facilitate solute focusing. The sorption/desorption phenomena could, perhaps, also be explained on the basis of ion-exchange and local pH junction effects. On-line preconcentration and analysis results obtained on sulfonated sol-gel columns were compared with those obtained on an uncoated fused silica capillary of identical dimensions using conventional sample injections. Using UV detection, the presented sample preconcentration technique provided a sensitivity enhancement factor (SEF) on the order of 3 x 10(3) for myoglobin, and 7 x 10(3) for asparagine.

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Section: Introductionmentioning

confidence: 99%

Negatively charged sol‐gel column with stable electroosmotic flow for online preconcentration of zwitterionic biomolecules in capillary electromigration separations

Fries

Malik³

2005

J of Separation Science

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“…Logical ways for literature. It is widely accepted that the main reason circumventing these effects are either to oppress the for this phenomenon results from the charged silanol dissociation of the silanol groups by running the separation at a very low pH (|2.5, see [2,3]) or, on the contrary, to depress the dissociation of the [5][6][7][8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Binding of proline- and hydroxyproline-containing peptides and proteins to the capillary wall

Hamrnı́ková

Mikšı́k

Deyl

et al. 1999

Journal of Chromatography A

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Sticking of peptides (as demonstrated by peak distortion) containing a high proportion of glycine and proline residues to the capillary wall was investigated. At acid pH where the carboxy terminal proline (e.g. Gly-Pro) is protonated, distinct sticking of these peptides occurred. On the contrary, the Pro-Gly peptide yielded a well shaped peak. At alkaline pH, where the situation was reversed, the peptide sticking most to the wall was Gly-Gly, while the behaviour of the dipeptides possessing N-or C-terminal proline did not suffer from sticking to the wall.It was concluded that the separation of simple proline-and glycine-containing dipeptides can be partly optimized by manipulating the pH of the background electrolyte; particularly if cetyltrimethylammonium bromide, methanol or acetonitrile is added to the run buffer (reversed polarity mode with cetyltrimethylammonium bromide). However, all attempts to resolve more complex mixtures of proline-(and hydroxyproline-) containing di-and tripeptides failed; addition of an organic modifier, i.e. methanol and acetonitrile, hexylamine, triethylamine and cetyltrimethylammonium bromide was unsuccessful. Such separations can be materialized by using simple 25 mmol / l phosphate buffer at pH 10.5 provided that the sample is dissolved in (aqueous) 17.5 mmol / l Brij or 33 mmol / l sodium dodecyl sulfate. These systems are also applicable to large polypeptides rich in proline, hydroxyproline and glycine: typically parent collagen a-chains, their dimers, trimers and higher polymers were successfully separated.

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“…Finally, Ferroukhi et al [65] have bonded and synthesized poly-7-benzyl (Lglutamate) (PBLG) in-situ on aminopropyl silica. Polymers similar to poly(methyl glutamate) (PMG) have already been coated by Engelhardt et al [66]. It was found that on this phase the mechanism of retention of amino acids depended on mobile-phase composition, showing there is a lyotropic effect; unfortunately no further details of this effect were forthcoming.…”

Section: Bonded Liquid-crystalline Polymersmentioning

confidence: 96%

Application of liquid crystals in liquid chromatography. From low- to high-molecular-weight liquid crystals

Gritti

Félix

2002

Chromatographia

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Key WardsColumn liquid chromatography Review of liquid-crystal stationary phases Bonded stationary phases Coated liquid-crystal polymers Molecular-shape recognition SummaryThe use of liquid crystals as stationary phases for liquid chromatography is reviewed. The synthetic pathways used for covalent immobilization of low-molecular-weight liquid crystals on the silica-gel surface are discussed. The techniques used to characterize stationary phase structure are also presented. Finally, the trend for replacement of low-molecular-weight liquid crystals by liquid-crystalline polymers, either coated or bonded, is described. Examples are given of the separation of specific chemical compounds on liquid-crystalline stationary phases.liquid crystal on the solid support. The three-dimensional liquid crystal system in GC thus becomes a two dimensional system in HPLC.We will describe first the different synthetic pathways used to bond low-molecular-weight (LMW) liquid-crystalline molecules to silica gel particles, and the physicochemical characterization and chromatographic properties of these liquidcrystal-based stationary phases for HPLC.The alternative use of liquid-crystalline polymers (LCP), either coated or bonded to silica, will also be presented and trends in the use of liquid crystals as stationary phases in HPLC will be introduced.

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Poly(methylglutamate)-coated surfaces in HPLC and CE

Cited by 47 publications

References 46 publications

Negatively charged sol‐gel column with stable electroosmotic flow for online preconcentration of zwitterionic biomolecules in capillary electromigration separations

Negatively charged sol‐gel column with stable electroosmotic flow for online preconcentration of zwitterionic biomolecules in capillary electromigration separations

Binding of proline- and hydroxyproline-containing peptides and proteins to the capillary wall

Application of liquid crystals in liquid chromatography. From low- to high-molecular-weight liquid crystals

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