Choosing the best capillary coatings based on mixtures of cationic and neutral double-chained surfactants for protein separation by capillary electrophoresis
Abstract
Background: Separation efficiency in capillary electrophoresis (CE) is mainly controlled by analyte adsorption onto the capillary wall and by local surface charge inhomogeneity (SCI). While wall adsorption can be reduced by appropriate capillary coatings, SCI remains difficult to control. Double-chained cationic surfactant coatings, particularly dimethyldioctadecylammonium bromide (DODAB), have shown excellent efficiency, but they also generate very strong electroosmotic flow (EOF) that shortens analysis times, decreases the apparent selectivity and can compromise protein resolution. Results: To achieve a better balance between separation efficiency and selectivity, this work systematically investigated two strategies for tuning the EOF of DODAB coatings: (i) mixing DODAB with the zwitterionic lipid, 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), and (ii) applying a sequential co-coating with the neutral polymer, polyoxyethylene 40 stearate (POE 40 stearate), onto the DODAB coating. EOF modulation using DSPC shifted the EOF from −77.8 ± 0.7 TU (1 TU = 1 × 10−9 m2 V−1 s−1) to 4.1 ± 0.6 TU at an equimolar DSPC/DODAB ratio, leading to improved resolution under the conditions investigated. POE 40 stearate provided stronger EOF suppression, but higher polymer concentrations were accompanied by substantial kinetic broadening. Significance: Both approaches were compared in terms of EOF control, kinetic performance, migration repeatability, and protein separation performance, including a systematic investigation of plate height H vs migration velocity u behavior. Graphical guides are proposed to assist in selecting cationic or neutral capillary coatings for protein CE in acidic conditions according to protein effective mobility, while considering both apparent selectivity and separation efficiency.
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BibTeX
@article{prakobdi2026choosing,
title = {{Choosing the best capillary coatings based on mixtures of cationic and neutral double-chained surfactants for protein separation by capillary electrophoresis}},
author = {Chirapha Prakobdi and Laurent Leclercq and Phoonthawee Saetear and Herve Cottet},
journal = {Analytica Chimica Acta},
year = {2026},
month = oct,
doi = {10.1016/j.aca.2026.346435},
url = {https://hal.science/hal-05848756v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Choosing the best capillary coatings based on mixtures of cationic and neutral double-chained surfactants for protein separation by capillary electrophoresis
AU - Chirapha Prakobdi
AU - Laurent Leclercq
AU - Phoonthawee Saetear
AU - Herve Cottet
PY - 2026
DA - 2026/10/24
JO - Analytica Chimica Acta
DO - 10.1016/j.aca.2026.346435
UR - https://hal.science/hal-05848756v1
AB - Background: Separation efficiency in capillary electrophoresis (CE) is mainly controlled by analyte adsorption onto the capillary wall and by local surface charge inhomogeneity (SCI). While wall adsorption can be reduced by appropriate capillary coatings, SCI remains difficult to control. Double-chained cationic surfactant coatings, particularly dimethyldioctadecylammonium bromide (DODAB), have shown excellent efficiency, but they also generate very strong electroosmotic flow (EOF) that shortens analysis times, decreases the apparent selectivity and can compromise protein resolution. Results: To achieve a better balance between separation efficiency and selectivity, this work systematically investigated two strategies for tuning the EOF of DODAB coatings: (i) mixing DODAB with the zwitterionic lipid, 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), and (ii) applying a sequential co-coating with the neutral polymer, polyoxyethylene 40 stearate (POE 40 stearate), onto the DODAB coating. EOF modulation using DSPC shifted the EOF from −77.8 ± 0.7 TU (1 TU = 1 × 10−9 m2 V−1 s−1) to 4.1 ± 0.6 TU at an equimolar DSPC/DODAB ratio, leading to improved resolution under the conditions investigated. POE 40 stearate provided stronger EOF suppression, but higher polymer concentrations were accompanied by substantial kinetic broadening. Significance: Both approaches were compared in terms of EOF control, kinetic performance, migration repeatability, and protein separation performance, including a systematic investigation of plate height H vs migration velocity u behavior. Graphical guides are proposed to assist in selecting cationic or neutral capillary coatings for protein CE in acidic conditions according to protein effective mobility, while considering both apparent selectivity and separation efficiency.
SN - 0003-2670
ER -