A hyperbranched polyethylenimine functionalized stationary phase for hydrophilic interaction liquid chromatography

Area of Science:

• Analytical Chemistry
• Chromatography Science

Background:

• Hydrophilic interaction liquid chromatography (HILIC) is crucial for separating polar compounds.
• Developing advanced stationary phases is key to improving HILIC performance.
• Polyethylenimine (PEI) offers abundant functional groups for enhanced interactions.

Purpose of the Study:

• To synthesize and characterize a novel hyperbranched stationary phase for HILIC.
• To evaluate the separation performance of the new phase for various polar analytes.
• To compare the new phase with commercial alternatives for selectivity.

Main Methods:

• Grafting polyethylenimine (PEI) onto silica gel to create the PEI-Sil stationary phase.
• Utilizing PEI-Sil in hydrophilic interaction liquid chromatography (HILIC).
• Testing separation of model polar compounds: organic acids, nucleosides, bases, amino acids, cephalosporins, and sugars.
• Operating PEI-Sil in ion chromatography mode for inorganic anion separation.

Main Results:

• PEI-Sil demonstrated excellent separation performance, including high stability and reproducibility.
• High separation efficiency was achieved, with plate counts around 74,000/m.
• PEI-Sil showed superior selectivity for inorganic anions compared to a commercial amino propyl column in ion chromatography mode.
• The hyperbranched structure and abundant amino groups of PEI contributed to effective polar analyte interactions.

Conclusions:

• The developed PEI-Sil stationary phase is highly effective for HILIC separations of polar compounds.
• PEI-Sil offers advantages in stability, reproducibility, efficiency, and selectivity.
• This novel material presents a promising alternative for chromatographic analysis of polar and ionic species.