Polymeric ionic liquid modified organic-silica hybrid monolithic column for capillary electrochromatography

Area of Science:

• Analytical Chemistry
• Separation Science
• Materials Science

Background:

• Development of advanced stationary phases for capillary electrochromatography (CEC) is crucial for improving separation efficiency.
• Hybrid monolithic columns offer unique advantages in terms of surface area and flow-through properties.
• Modification of these columns with polymeric ionic liquids (PILs) can impart desirable chromatographic characteristics.

Purpose of the Study:

• To synthesize and characterize a novel polymeric ionic liquid (PIL) modified hybrid monolithic column for CEC.
• To evaluate the column's performance in terms of electroosmotic flow (EOF) stability and separation capabilities.
• To assess the reproducibility of the developed chromatographic method.

Main Methods:

• Synthesis of a mercaptopropyl-functionalized (MP-silica) hybrid monolithic column via sol-gel process.
• Modification of the MP-silica column with a specific PIL (PImC₈-silica).
• Characterization using Fourier-transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS).
• CEC separation of aromatic hydrocarbons, alkylbenzenes, and phenols using phosphate buffers with varying acetonitrile ratios.
• Evaluation of method reproducibility through relative standard deviations (RSDs) of migration times.

Main Results:

• The PImC₈-silica hybrid monolithic column demonstrated a strong and stable reversed electroosmotic flow (EOF) over a wide pH range (3.0-8.0).
• Effective separation of aromatic hydrocarbons, alkylbenzenes, and phenols was achieved.
• High reproducibility was observed, with run-to-run, day-to-day, and column-to-column RSDs within acceptable limits (0.26-5.7%).

Conclusions:

• The PIL-modified hybrid monolithic column is a promising material for CEC applications.
• The column's stable EOF and good separation performance make it suitable for analyzing complex mixtures.
• The developed method exhibits excellent reproducibility, supporting its practical utility in analytical laboratories.