Capillary electrochromatography with a silica column with a dynamically modified cationic surfactant.

Area of Science:

• Analytical Chemistry
• Separation Science

Background:

• Capillary electrochromatography (CEC) is a powerful separation technique.
• Modifying stationary phases is crucial for optimizing CEC performance.
• Bare silica columns often face challenges with peak tailing, especially for basic analytes.

Purpose of the Study:

• To introduce a novel dynamically modified silica-capillary electrochromatography (CEC) method.
• To investigate the separation of neutral and nitrogen-containing solutes using this new CEC mode.
• To evaluate the efficiency and reproducibility of the dynamically modified column.

Main Methods:

• Dynamic modification of a bare silica capillary column using cetyltrimethylammonium bromide (CTAB) in the mobile phase.
• Adsorption of CTAB onto the silica surface to create a hydrophobic stationary phase.
• Separation of neutral and nitrogen-containing solutes via CEC.
• Investigation of mobile phase composition effects on separation.

Main Results:

• Achieved high separation efficiency with up to 71,500 theoretical plates/m.
• Demonstrated excellent reproducibility with relative standard deviations of 4.7% for t0 and 4.9% for toluene's capacity factor over 20 runs.
• Successfully separated neutral solutes.
• Effectively eliminated peak tailing for basic solutes by blocking silica surface adsorption with CTAB.

Conclusions:

• Dynamically modified silica-capillary electrochromatography with CTAB is a viable and efficient method for separating neutral and basic compounds.
• The method offers high efficiency and reproducibility, making it suitable for routine analysis.
• The dynamic modification effectively addresses peak tailing issues associated with basic analytes in CEC.