Cycloaliphatic epoxy resin coating for capillary electrophoresis

Area of Science:

• Analytical Chemistry
• Separation Science
• Materials Science

Background:

• Capillary electrophoresis (CE) relies on capillary coatings to control electroosmotic flow (EOF) and minimize analyte adsorption.
• Traditional coatings often face limitations in pH stability or effectiveness for diverse analytes like proteins.

Purpose of the Study:

• To develop and evaluate a novel cycloaliphatic epoxide-based resin coating for fused-silica capillaries.
• To assess the coating's impact on electroosmotic flow (EOF) and protein adsorption.
• To demonstrate the coating's utility in separating proteins and peptides using CE.

Main Methods:

• Fused-silica capillaries were treated with silane and coated with a cycloaliphatic epoxide-based resin.
• The resin was crosslinked using a curing agent.
• The coated capillaries were tested for EOF reduction across a pH range of 3-10.
• Protein and peptide separations were performed, and separation efficiencies were determined.

Main Results:

• The epoxy resin coating significantly reduced EOF from pH 3 to 10.
• The hydrophilic coating effectively suppressed protein adsorption.
• Separation efficiencies exceeding 400,000 theoretical plates were achieved for proteins and peptides.
• Excellent reproducibility was observed, with relative standard deviations in migration times below 0.8% for proteins.

Conclusions:

• The cycloaliphatic epoxide-based resin provides an effective and stable coating for fused-silica capillaries in CE.
• This coating method offers a simple, rapid, and efficient approach for separating proteins and peptides.
• The developed coating addresses key challenges in CE, improving separation performance and reproducibility.