Novel PEI/Zein core-shell composite as mixed-mode stationary phase for high performance liquid chromatography

Area of Science:

• Materials Science
• Analytical Chemistry
• Chromatography

Background:

• Developing advanced stationary phases is crucial for effective chromatographic separations.
• Existing silica-based stationary phases can exhibit strong adsorption issues.
• Composite materials offer tunable properties for enhanced separation performance.

Purpose of the Study:

• To prepare and characterize a novel polyethyleneimine (PEI)/zein co-modified core-shell stationary phase (PEI/Zein@SiO2).
• To evaluate the separation capabilities of the PEI/Zein@SiO2 column for both hydrophilic and hydrophobic compounds.
• To investigate the potential of this new material in chromatographic applications.

Main Methods:

• Preparation of PEI/zein co-modified silica nanoparticles.
• Characterization of the stationary phase using various techniques to determine morphology and surface area.
• Chromatographic analysis of hydrophilic (nucleosides, bases, antibiotics) and hydrophobic (flavones) compounds using mixed-mode chromatography.
• Investigation of separation performance and retention mechanisms.

Main Results:

• The PEI/Zein@SiO2 stationary phase demonstrated effective separation of nucleosides, bases, and antibiotics in hydrophilic interaction mode.
• Flavones were successfully separated in reversed-phase mode due to the hydrophobic nature of zein.
• The column exhibited excellent performance for both hydrophilic and hydrophobic compounds via a mixed double mode.
• The material avoided dissolution of zein and masked strong adsorption from silica hydroxyl groups.
• Satisfactory stability and reproducibility were achieved.

Conclusions:

• The PEI/Zein@SiO2 column provides a versatile platform for the separation and analysis of diverse analytes.
• Zein modification significantly enhances the separation selectivity of the stationary phase for complex samples.
• This novel material shows potential for application in stationary phase packing for advanced chromatography.