Switching Separation Migration Order by Switching Electrokinetic Regime in Electrokinetic Microsystems

Area of Science:

• Analytical Chemistry
• Separation Science
• Microfluidics

Background:

• Analyte migration order is crucial for analytical separation methods.
• Insulator-based electrokinetic (iEK) separation is a powerful microfluidic technique.
• Understanding electrokinetic regimes is key to optimizing separations.

Purpose of the Study:

• To investigate the manipulation of microparticle migration order in iEK.
• To explore the impact of linear versus nonlinear electrokinetic regimes on separation.
• To assess the potential for altering particle elution order and improving separation resolution.

Main Methods:

• Studied three distinct microparticle mixtures (binary and tertiary).
• Performed separations twice: once under low voltage (linear regime) and once under high voltage (nonlinear regime).
• Analyzed separation performance based on elution order and separation resolution (Rs).

Main Results:

• Particle elution order was successfully altered by switching between linear and nonlinear electrokinetic regimes.
• Nonlinear electrophoresis, dominant in the nonlinear regime, discriminated particles by size and shape.
• Higher separation resolution (Rs) was achieved in the nonlinear regime compared to the linear regime.

Conclusions:

• Switching electrokinetic regimes effectively controls microparticle migration order in iEK systems.
• The nonlinear electrokinetic regime offers superior separation performance for microparticles.
• Findings have potential applications in analyzing complex micron-sized bioparticle samples.