Enhanced-Fluidity Liquid Chromatography-Mass Spectrometry for Intact Protein Separation and Characterization.

Area of Science:

• Analytical Chemistry
• Chromatography
• Biochemistry

Background:

• Increasing demand for efficient intact protein separation techniques.
• Conventional liquid chromatography (LC) limitations in speed and resolution.
• Need for improved methods in large-scale peptide and protein analysis.

Purpose of the Study:

• To investigate the application of enhanced-fluidity liquid chromatography (EFLC) to hydrophobic interaction chromatography (HIC) for protein separation.
• To evaluate the impact of liquefied carbon dioxide (CO2) on protein chromatographic behavior, charge state distributions (CSDs), and ionization efficiencies.
• To assess EFLC as a potential 'supercharging' reagent for electrospray ionization (ESI) mass spectrometry.

Main Methods:

• Implementation of enhanced-fluidity liquid chromatography (EFLC) using liquefied CO2 added to conventional liquid mobile phases.
• Application of EFLC to hydrophobic interaction chromatography (HIC) stationary phases.
• Evaluation of chromatographic properties, charge state distributions (CSDs), and ionization efficiencies of proteins under EFLC conditions.

Main Results:

• EFLC demonstrated superior chromatographic performance over conventional LC, including reduced analysis time, improved peak shapes, and higher plate numbers.
• The addition of liquefied CO2 enhanced protein diffusivity and decreased mobile phase viscosity.
• EFLC acted as an electrospray ionization (ESI)-friendly 'supercharging' reagent without compromising chromatographic efficiency.

Conclusions:

• EFLC is a novel and effective technique for enhancing protein separation in HIC.
• Liquefied CO2 in EFLC improves chromatographic efficiency and offers 'supercharging' benefits for ESI-MS.
• This method holds potential for improving peptide and protein identification in large-scale applications.