Surface modification based on Si-O and Si-C sublayers and a series of N-substituted acrylamide top-layers for capillary electrophoresis

Cecilia Gelfi, Mario Curcio, Pier Giorgio Righetti, Roberto Sebastiano, Attilio Citterio, Hossein Ahmadzadeh, Norman J. Dovichi

Research output: Contribution to journalArticlepeer-review

Abstract

Two approaches were used to prepare a series of surface-modified capillaries. In the first, a sublayer was formed by coupling γ-methacryloxypropyltrimethoxysilane to the surface silanol groups forming an SI-O bond; a top layer was then formed by polymerizing acrylamide in the capillary, which reacted with the sublayer. In the second approach, a sublayer was formed by silanol chlorination, followed by Grignard coupling of vinylmagnesium bromide to form an Si-C bond at the surface; a top layer was formed by polymerizing either. acrylamide (AA), dimethylacrylamide (DMA), N-acryloylaminoethoxyethanol (AAEE), or N-acryloylaminopropanol (AAP) onto the sublayer. The Si-C-poly(AA) capillaries were more stable and produced an approximately 10-fold lower electroosmotic flow compared to the Si-O-poly(AA) capillaries. The Si-C sublayer was used to compare the performance of all four top layers. Electroosmotic flow decreased in the order: Si-O-poly(AA), Si-C-poly(AA), Si-C-poly(AAEE), Si-C-poly(DMA), and Si-C-poly(AAP). Si-C-poly(AA) showed evidence of irreversible degradation at pH 9 already after 40-50 runs. Si-C-polyAAP-coated capillaries demonstrated superior efficiency and migration time reproducibility for a number of alkaline proteins and for fluorescently labeled ovalbumin. Excellent performance was maintained, in the case of poly(AAP), for a least 300 runs (of 30 min duration) at pH 9.0.

Original languageEnglish
Pages (from-to)1677-1682
Number of pages6
JournalElectrophoresis
Volume19
Issue number10
Publication statusPublished - Jul 1998

Keywords

  • Capillary electrophoresis
  • Coating
  • Ekectroosmosis
  • N-substituted acrylamide
  • Silica

ASJC Scopus subject areas

  • Clinical Biochemistry

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