Fast and easy coating for capillary electrophoresis based on a physically adsorbed cationic copolymer

Area of Science:

• Analytical Chemistry
• Separation Science
• Polymer Chemistry

Background:

• Capillary electrophoresis (CE) separations are often limited by electroosmotic flow (EOF) variability and analyte adsorption.
• Developing robust and adaptable capillary coatings is crucial for improving CE performance.

Purpose of the Study:

• To synthesize and characterize a new ethylpyrrolidine methacrylate (EPyM) and methylmethacrylate (MMA) copolymer for CE capillary coatings.
• To investigate the copolymer's ability to control EOF and improve separation efficiency and reproducibility.

Main Methods:

• Physically adsorbed coating of EPyM/MMA copolymer onto capillary electrophoresis capillaries.
• Systematic variation of copolymer composition, background electrolyte (BGE), and pH.
• Evaluation of electroosmotic flow (EOF) direction and magnitude.
• Assessment of separation performance, including analysis time, resolution, and reproducibility (RSD values).

Main Results:

• Reproducible EOF was achieved across different pH and polymer compositions (RSD < 1.9% daily, < 0.5% inter-day, < 0.6% inter-capillary).
• EPyM/MMA coatings significantly reduced analysis times and improved resolution.
• Effective separation of basic proteins by minimizing wall adsorption.
• Enhanced separation of samples with both positive and negative analytes.
• Improved separation of nucleosides via additional chromatographic-like interactions.

Conclusions:

• The EPyM/MMA copolymer provides a versatile and reproducible coating for capillary electrophoresis.
• This coating technology offers significant improvements in separation efficiency, speed, and analyte compatibility.
• The EPyM/MMA coating is a promising advancement for various CE applications, including protein and nucleoside analysis.