Quaternary ammonium substituted agarose as surface coating for capillary electrophoresis

Abstract

A novel positively charged polymer of quaternary ammonium substituted agarose (Q-agarose) has been synthesized and explored for use as a coating in capillary electrophoresis. The fast and simple coating procedure is based on a multi-site electrostatic interaction between the polycationic agarose polymer and the negatively charged fused-silica surface. By simply flushing fused-silica capillaries with hot polymer solution a positively charged, hydrophilic deactivation layer is achieved. The polymer surface provides an intermediate electroosmotic flow of reversed direction, over a range of pH 2-11, compared to unmodified fused-silica. The coating procedure was highly reproducible with an RSD of 4%, evaluated as the electroosmotic flow mobility for 30 capillaries prepared at 10 different occasions. The application of Q-agarose coated capillaries in separation science was investigated using a set of basic drugs and model proteins and peptides. Due to the intermediate electroosmotic flow generated, the resolution of basic drugs could be increased, compared to using bare fused-silica capillaries. Moreover, the coating enabled separation of proteins and peptides with efficiencies up to 300.000 plates m(-1).

CE‐ESI‐MS of biological anions in plastic capillaries at high pH

“…Coating of fused-silica capillaries is the most effective way to modify the EOF, improve separation selectivities, and reduce analyte adsorption to the inner capillary wall [8][9][10][11][12][13]. However, the chemical stability of currently available coated capillaries is limited, and the accessible pH range is comprised between 2 and 10 [12,13].…”

“…Coating of fused-silica capillaries is the most effective way to modify the EOF, improve separation selectivities, and reduce analyte adsorption to the inner capillary wall [8][9][10][11][12][13]. However, the chemical stability of currently available coated capillaries is limited, and the accessible pH range is comprised between 2 and 10 [12,13]. Plastics have become important materials for manufacturing microfluidic devices for electrodriven separations [14,15], but only a few CE experiments have been reported in the last 10 year using polymeric capillary columns [16][17][18][19][20][21][22][23][24][25][26][27].…”

An N‐methylpolyvinylpyridinium cationic polymer for capillary coating in electrophoresis of proteins and peptides

“…In this last case, the capillary-coating procedure is reduced to a simple, three-step rinsing protocol, comprising deprotonation of surface silanols via bathing in a basic solution that will maximize the negative surface charge, adsorption of the polymer and a final rinse for removing excess polymer not adsorbed onto the surface. The polymeric coating comprise polyethylenimine [16], polybrene [17], poly(diallyldimethyl ammonium chloride) [18], polyarginine [19], chitosan [20], pyrrolidone-containing copolymers [21] quaternary ammonium-substituted agarose [22] or cationic coatings consisting of successive multiple ionic polymer layers [23]. In more recent times, a new cationic polyamine, made by copolymerizing 1,2-bis (3-aminopropylamino)ethane with epichlorohydrine, has been reported [24][25][26].…”

Cationic amylopectin derivatives as additives for analysis of proteins in capillary electrophoresis

“…Starch consists of extremely polydispersed anhydroglucose homopolymers in the form of amylose and amylopectin. Amylopectin, the major component of starch (70-80%), is a highly branched polymer consisting of relatively short segments of D-glucopyranose residues (20)(21)(22)(23)(24)(25) linked by a-D-(1,4) bonds, and connected by a-D-(1,6)-glucosidic linkages, with a molecular weight ranging from 10610 6 to 500610 6 .…”