Control of the EOF in CE using polyelectrolytes of different charge densities

Danger, Grégoire; Ramonda, Michel; Cottet, Hervé

doi:10.1002/elps.200600360

Cited by 45 publications

(38 citation statements)

References 35 publications

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“…1A), and consequently the viscosity of the fluid adjacent to the wall increases significantly [4,12,13]. Another crucial aspect is that polymer coating modifies the magnitude of the z-potential, and even the sign, depending on the electrical charge of polymers [3,14,15].…”

Section: Polymer Adsorptionmentioning

confidence: 99%

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The EOF of polymer solutions

Olivares

Vera‐Candioti²,

Berli

2009

Electrophoresis

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The EOF of polymer solutions is analysed in the framework of continuum fluid mechanics and the standard electrokinetic model. Two key aspects are taken into consideration: the non-Newtonian character of the fluid and the polymer concentration near the interface, which greatly modify the fluid viscosity in the region where electroosmosis takes place. A satisfactory mathematical model is derived for the electroosmotic mobility of solutions that present polymer depletion at the wall. The case of solutions containing polymers that adsorb onto the wall is briefly reviewed, and a preliminary approach is discussed for the limit of strong polymer adsorption. In order to illustrate the theoretical discussions, experimental data obtained from aqueous solutions of carboxymethyl cellulose in fused-silica capillaries are presented. Relevant results are observed, which are appropriately captured by the modelling proposed. The fundamental phenomena discussed in this work are of interest in microfluidics and electrophoresis.

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Section: Polymer Adsorptionmentioning

confidence: 99%

“…In the second case, the EOF is strongly diminished and even suppressed, as the viscosity of the fluid adjacent to the wall is significantly enhanced [12,13]. Indeed, as the z-potential is also modified, polymer coating is the mechanism normally used to control the EOF in CE [14,15].…”

Section: Introductionmentioning

confidence: 98%

The EOF of polymer solutions

Olivares

Vera‐Candioti²,

Berli

2009

Electrophoresis

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“…Katayama et al [27] modulated the EOF and the resolution of enantiomers by coupling a neutral capillary with a polyelectrolyte multilayer coated capillary [24]. Recently, our group proposed a new method for controlling the EOF, based on the use of polyelectrolytes of different charge densities [28].…”

Section: Gré Goire Danger Robert Pascal Hervé Cottetmentioning

confidence: 98%

Non‐uniform surface charge distributions in CE: Theoretical and experimental approach based on Taylor dispersion

2008

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The control of the EOF direction and magnitude remains one of the more challenging issues for the optimization of separations in CE. In this work, we investigated the possibility to use non-uniform surface charge distribution for the modulation of the EOF in CE. Non-uniform zeta potentials were obtained by modifying a section of the capillary surface using adsorption of polyelectrolytes. Three different methods were studied: (i) partial polycation coating on a fused silica capillary, (ii) partial polycation (or polyanion) coating on polyelectrolyte multilayers, and (iii) partial polycation coating on a capillary previously modified with poly(ethylene oxide). The magnitude and the direction of the EOF as a function of the coated capillary length were first studied. The stability of the EOF and the separation performances were also considered taking two dialanine diastereoisomers as model compounds. In partially coated capillaries, the average solvent flow is the sum of two contributions: a non-dispersive electroosmotic contribution related to the capillary surface charge, and a dispersive hydrodynamic contribution that depends on the difference of surface charge between the coated and the non-coated capillary zones. To get a better insight into the influence of the hydrodynamic contribution to the total peak dispersion, the peak variances corresponding to the Taylor dispersion, the injection plug, and the axial diffusion were calculated. This work demonstrates that peak dispersion in a capillary partially coated by the inlet end is different from that obtained when the coating is performed by the outlet end. Experimentally, the combination of a partially coated capillary with a large volume sample stacking preconcentration step can be used for injecting up to 95% of the capillary volume. This approach leads to a preconcentration factor of 60 compared with CZE with classical injection.

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“…The use of charged polyelectrolytes for capillary coating has become popular in CE, especially for peptides and proteins analysis to prevent analyte adsorption [43][44][45][46][47][48][49][50] and to control the EOF [51][52][53][54]. The polyelectrolytes are generally highly adsorbed to the capillary via electrostatic, hydrogen and even hydrophobic interactions [10,17,18,22,23,[55][56][57].…”

Section: Pdadmac-coated Capillarymentioning

confidence: 99%

Use of coated capillaries for the electrophoretic separation of stereoisomers of a growth hormone secretagogue

et al. 2009

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The diastereoisomeric separation of peptidomimetics of hexarelin, a strong growth hormone secretagogue, in CE has been studied. Highly sulfated-gamma-CD was found to be an appropriate selector for the separation of the stereoisomers. However, non-repeatable analyses were obtained on bare fused silica capillary due to the progressive adsorption of the analytes on the capillary wall. Two types of polyelectrolyte coating agents were tested to prevent this phenomenon. Coating with neutral polyethylene oxide was found to be efficient but resulted in a very long analysis time (about 40 min). Coating with cationic poly(diallyldimethylammonium) chloride was found both to prevent analyte adsorption, reduce analysis time and alter separation selectivity. EOF measurement revealed that the highly sulfated-gamma-CDs were strongly adsorbed on the poly(diallyldimethylammonium) chloride coating surface yielding a stable strong cathodic EOF, which considerably reduced analysis time (about 12 min). Very good repeatability of analysis was obtained (RSD(migration time)<1%).

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Control of the EOF in CE using polyelectrolytes of different charge densities

Cited by 45 publications

References 35 publications

The EOF of polymer solutions

The EOF of polymer solutions

Non‐uniform surface charge distributions in CE: Theoretical and experimental approach based on Taylor dispersion

Use of coated capillaries for the electrophoretic separation of stereoisomers of a growth hormone secretagogue

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