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Electroosmotic flow suppression in capillary electrophoresis: Chemisorption of trimethoxy silane‐modified polydimethylacrylamide
Author(s) -
Cretich Marina,
Chiari Marcella,
Pirri Giovanna,
Crippa Alessandro
Publication year - 2005
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200410368
Subject(s) - capillary electrophoresis , silane , covalent bond , polymer , adsorption , capillary action , chemistry , coating , silanes , chemical engineering , capillary condensation , chemisorption , copolymer , capillary surface , aqueous solution , polymer chemistry , electrophoresis , materials science , chromatography , organic chemistry , composite material , engineering
Adsorbed polymers are widely used to suppress electroosmotic flow (EOF) in capillary electrophoresis (CE). Polymeric coatings, physisorbed onto the surface of the capillary wall, are often unstable under harsh conditions. This can be attributed to the reversible nature of the coating which becomes apparent when the adsorbed layer competes with a second species in the electrophoresis buffer solution for attachment/interaction with the capillary surface. In an effort to overcome the problem of coating instability, trimethoxysilane‐modified polydimethylacrylamide was synthesized. This copolymer rapidly adsorbs on the wall from ultradilute aqueous solutions. After incubation at a temperature of 60°C silyl groups, which extend from the polymer backbone, form condensation bonds with the silanols on the capillary surface. This enables subsequent formation of strong covalent bonds between the copolymer and the capillary wall. In this research, we establish that physisorption of polymer chains to the surface is essential for close alignment of surface and polymer silane groups which facilitates the formation of covalent bonds.