Adjusting selectivity in micellar electrokinetic capillary chromatography with 1,2-hexanediol

Area of Science:

• Analytical Chemistry
• Separation Science

Background:

• Micellar electrokinetic capillary chromatography (MECC) is a powerful separation technique.
• Optimizing selectivity in MECC is crucial for resolving complex mixtures.
• Sodium dodecyl sulfate (SDS) is a common micelle-forming surfactant in MECC.

Purpose of the Study:

• To introduce and evaluate 1,2-hexanediol as a novel micelle modifier for MECC.
• To investigate the impact of 1,2-hexanediol on MECC selectivity and separation performance.
• To demonstrate the utility of 1,2-hexanediol in separating challenging analytes.

Main Methods:

• Investigated 1,2-hexanediol as a class I organic modifier affecting SDS micelles.
• Assessed the effects of 1,2-hexanediol on critical micelle concentration, electroosmotic flow, and electrophoretic mobility.
• Evaluated selectivity changes for various model compounds, including hydrogen-bonding and non-hydrogen-bonding analytes.
• Applied 1,2-hexanediol in the separation of dansylated amino acids.

Main Results:

• 1,2-Hexanediol improved resolution at concentrations as low as 20 mM by altering SDS micelle selectivity.
• Hydrogen-bonding analytes showed decreased interaction with micelles, while non-hydrogen-bonding analytes increased interaction.
• Eighteen of twenty dansylated amino acids were resolved with resolution >1.6 within 1600 s using 1,2-hexanediol and isopropanol.
• 1,2-Hexanediol had minimal impact on the migration time window below 100 mM.

Conclusions:

• 1,2-Hexanediol is an effective micelle modifier for enhancing MECC selectivity.
• This modifier offers improved resolution and separation efficiency for dansylated amino acids.
• 1,2-Hexanediol presents a valuable tool for optimizing MECC separations.