Porous Organic Cage-Embedded C10-Modified Silica as HPLC Stationary Phase and Its Multiple Separation Functions

Area of Science:

• Analytical Chemistry
• Materials Science
• Chromatography

Background:

• Development of novel stationary phases is crucial for advancing High-Performance Liquid Chromatography (HPLC).
• Existing C18 columns have limitations in selectivity for complex mixtures.
• Molecular cages offer unique structural properties for chromatographic applications.

Purpose of the Study:

• To synthesize and characterize a novel multifunctional stationary phase, RCC3-C10@silica, for HPLC.
• To evaluate the chiral resolution and separation capabilities of the new stationary phase.
• To compare the performance of RCC3-C10@silica with traditional C18 columns.

Main Methods:

• Covalent bonding of Reduced Imine Cage (RCC3) to silica spheres.
• Modification with non-polar C10 groups to create the RCC3-C10@silica stationary phase.
• Characterization using infrared spectroscopy, thermogravimetric analysis, and nitrogen adsorption-desorption.
• Evaluation of separation performance in reversed-phase and hydrophilic modes for various compound classes and chiral/achiral mixtures.

Main Results:

• Successful synthesis and characterization of the RCC3-C10@silica stationary phase confirmed by multiple analytical techniques.
• Excellent chiral resolution was achieved for several chiral alcohols (e.g., resolution up to 4.09).
• Separation and analysis of 70 compounds across 8 diverse classes, including phenols, nucleosides, and flavonoids.
• Demonstrated superior chromatographic selectivity (separation, aromatic, polar) compared to commercial C18 columns.
• Identified multifunctional separation mechanisms involving hydrophobic, π-π, hydrogen bonding, and steric interactions.

Conclusions:

• The novel RCC3-C10@silica stationary phase exhibits superior and versatile separation performance.
• Its multifunctional nature, stemming from synergistic interactions, makes it suitable for analyzing complex chiral and achiral mixtures.
• This development offers promising applications for advanced chromatographic separations.