Three versus five micrometer chlorinated polysaccharide-based packings in chiral capillary electrochromatography:...

Area of Science:

• Analytical Chemistry
• Separation Science

Background:

• Previous performance evaluations of capillary electrochromatography (CEC) columns indicated that smaller particle diameters did not consistently result in higher efficiencies.
• This study further investigates the relationship between particle size and column efficiency in CEC.

Purpose of the Study:

• To examine the phenomenon where smaller particle diameters do not always generate higher efficiencies in CEC.
• To optimize packing procedures for chlorinated polysaccharide-based chiral stationary phases (CSPs) to achieve high efficiency and precision in chiral separations.

Main Methods:

• Analysis of naphthalene and trans-stilbene oxide on 3 µm and 5 µm CSPs using voltages from 5 to 30 kV.
• Evaluation of Van Deemter curves to assess column efficiencies.
• Systematic evaluation of nine different packing procedures for both 3 µm and 5 µm CSPs.
• Statistical evaluation of packing variability and precision estimates.

Main Results:

• Neither 3 µm nor 5 µm particle sizes consistently yielded the highest efficiencies across all tested conditions.
• Column efficiencies were significantly influenced by the packing procedure, not solely by particle size.
• The optimal packing procedure involved using an MeOH-slurry followed by an 8-hour water rinsing step.
• This optimized procedure resulted in columns with high efficiencies for chiral separations and good precision (low relative standard deviation - RSD).

Conclusions:

• The efficiency of CEC columns is not solely dependent on smaller particle diameters; packing methodology plays a critical role.
• An optimized packing procedure, specifically an MeOH-slurry with an extended water rinse, is crucial for achieving high-efficiency and precise chiral separations in CEC.
• These findings provide valuable insights for the preparation of high-performance CEC columns.