Coating of open tubular capillaries with discoidal and spherical high‐density lipoprotein particles in electrochromatography

Abstract

A new method was developed for the coating of fused-silica capillaries with human high-density lipoproteins (HDLs) for use in electrochromatography. The HDL particles used for the coating differed in particle shape and composition. Both discoidal and spherical particles formed a monolayer on the inner silica wall as confirmed by atomic force microscopy. The effect of coating conditions, such as HDL concentration and coating time, was investigated with spherical HDL particles. Examination of the influence of pH on the coating stability also allowed the determination of pI values for the HDL particles attached to the capillary wall. The pI values for spherical and discoidal HDL particles were close to 5.0. The repeatabilities of the EOF mobility and the retention factors of the uncharged steroid hormones used as model compounds were exploited in the evaluation of the coating stability. The optimal coating was achieved with 0.1 mg/mL HDL protein and 50 min flushing with coating solution followed by 15 min standing time. Electrochromatography with HDL-coated open tubular capillaries offers a new tool for the study of HDL particle structure and transformations.

Surface initiated polymerization of a cationic monomer on inner surfaces of silica capillaries: Analyte separation by capillary electrophoresis versus polyelectrolyte behavior

“…The heterogeneity of the lipoproteins and their unfavorable and strong adsorption onto fused-silica capillary wall in capillary electrophoresis make their separation demanding [35]. HDL (pI 5.0) and LDL (pI 5.5) exhibit net positive charges at pH range 3-5 [36,37]. Cationic PMOTAC coating greatly diminished the adsorption of lipoprotein particles, and satisfactory separation was obtained in capillaries coated with PMOTAC at pH 3 and 4 ( Fig.…”

Multi‐walled carbon nanotube composites with polyacrylate prepared for open‐tubular capillary electrochromatography

“…Some Jian-Lian Chen Te-Ling Lu Yi-Chen Lin nanomaterials, including latex [11], lipoprotein [12,13], silica [14,15], titanium oxide [16,17], gold [18][19][20], and carbon nanotubes (CNT) [21][22][23][24][25], have been used in OT-CEC. However, only a few examples involved in chemical bonding of these materials onto OT capillaries exist.…”

Analytical Conditions and Separation Performance of Capillary Chromatography Based on the Tube Radial Distribution of Aqueous-Organic Mixture Carrier Solvents under Laminar-Flow Conditions

“…For example, the inner wall of the tube was coated with silicone grease (SE-30 8 ) or modified with a monolayer particle phase. 9 Porous silica structures were also introduced on the wall by dynamic or static coating techniques, [10][11][12] and various polymeric siloxanes were immobilized on the walls. 13,14 We modified the inner walls with specific functional groups or molecules, such as phenylboronic acid, iminodiacetic acid, and antibodies for capillary chromatography to take advantage of specific interactions between the solutes and the modified walls.…”