Separation of proteins by cation-exchange sequential injection chromatography using a polymeric monolithic column

Area of Science:

• Analytical Chemistry
• Chromatography
• Materials Science

Background:

• Sequential injection chromatography (SIC) has been limited to small molecule separations.
• High molar mass compounds, such as proteins, have not been effectively separated using SIC.
• Novel monolithic column materials are needed for advanced chromatographic applications.

Purpose of the Study:

• To develop and validate a sequential injection chromatography (SIC) method for protein separation.
• To prepare and characterize a novel poly(glycidyl methacrylate-co-ethylene dimethacrylate) (GMA-co-EDMA) monolithic column.
• To investigate the potential of cation-exchange chromatography for protein analysis using SIC.

Main Methods:

• Preparation of a GMA-co-EDMA monolithic column via free radical polymerization in fused silica-lined stainless steel tubing.
• Modification of the monolithic column with iminodiacetic acid (IDA) for cation-exchange properties.
• Protein separation using a gradient of NaCl generated in a holding coil within the SIC system.

Main Results:

• Successful separation of myoglobin, ribonuclease A, cytochrome C, and lysozyme within 10 minutes.
• Demonstrated reproducible protein separation using a dynamically generated salt gradient in the SIC system.
• Elution order correlated with protein isoelectric points, confirming a cation-exchange mechanism.

Conclusions:

• The developed SIC method with an IDA-modified monolithic column is effective for protein separation.
• This approach expands the application of SIC to high molar mass compounds like proteins.
• The study highlights the potential of monolithic materials in advanced chromatographic techniques.