Analyte zone sharpening in pressurized capillary electrochromatography based on electrophoretic migration under a...

Area of Science:

• Analytical Chemistry
• Separation Science
• Chromatography

Background:

• Capillary electrochromatography (CEC) offers high separation efficiency.
• Optimizing analyte band width is crucial for improving resolution in CEC.

Purpose of the Study:

• To investigate peak width reduction and peak height enhancement of angiotensins in hydrophilic interaction pressurized CEC.
• To explore the mechanism of perchloric acid adsorption and release from the stationary phase.
• To demonstrate the application of this method for improved separation efficiency.

Main Methods:

• Hydrophilic interaction pressurized capillary electrochromatography with gradient elution.
• Use of mobile phases containing perchloric acid.
• Detection using a contactless conductivity detector.
• Application of high voltage to the system.

Main Results:

• Significant peak width reduction and peak height enhancement observed for angiotensins.
• Perchloric acid adsorption on the stationary phase at high acetonitrile content and release during gradient elution.
• Formation of a concentrated perchloric acid zone affecting analyte migration.
• Demonstrated band width reduction and enhanced separation efficiency in reversed-phase pressurized CEC.
• Improved resolution from 2.7 to 4.3 for benzoic acid and 1-naphthalene sulfonic acid using field-amplified stacking.

Conclusions:

• The manipulation of perchloric acid concentration gradients can effectively reduce analyte band width.
• This technique significantly enhances separation efficiency and resolution in pressurized CEC.
• The method provides a novel approach for on-column concentration and improved chromatographic performance.