Development of the resolution theory for electrophoretic exclusion

Area of Science:

• Analytical Chemistry
• Separation Science
• Microfluidics

Background:

• Electrophoretic exclusion is a technique for differentiating species in solution near a channel entrance.
• It has been demonstrated in both benchtop and microdevice systems.
• Separation relies on differences in electrophoretic velocity relative to hydrodynamic flow.

Purpose of the Study:

• To theoretically assess the resolution of electrophoretic exclusion.
• To compare the performance of electrophoretic exclusion to traditional separation techniques.
• To provide a theoretical framework for understanding the capabilities of this separation method.

Main Methods:

• Theoretical calculations were performed to determine resolution limits.
• Performance was quantified by the smallest difference in electrophoretic mobilities for complete separation (R = 1.5).
• Calculated values for minimum mobility difference and peak capacity were compared with published experimental data.

Main Results:

• The theoretical analysis indicates that the closest resolvable species (Δμmin) differ by approximately 10(-13) m(2)/Vs.
• A peak capacity (nc) of 1000 was calculated, suggesting high separation potential.
• Published experimental data showed good agreement with the theoretical calculations.

Conclusions:

• Electrophoretic exclusion offers significant potential for high-resolution species separation.
• Theoretical assessment provides a valuable benchmark for experimental design and performance evaluation.
• This technique is promising for various analytical applications requiring sensitive differentiation of analytes.