Low EOF rate measurement based on constant effective mobility in microchip CE

Area of Science:

• Analytical Chemistry
• Separation Science
• Microfluidics

Background:

• Accurate measurement of electroosmotic flow (EOF) is crucial in microchip electrophoresis (CE).
• Low EOF rates, particularly in modified microchannels, present significant analytical challenges.
• Existing methods for determining low EOF can be complex or time-consuming.

Purpose of the Study:

• To introduce a rapid and accurate method for quantifying low electroosmotic flow (EOF) rates in microchip CE.
• To provide a reliable technique for analyzing samples in microchannels with minimal EOF.
• To facilitate precise electrophoretic separations in challenging microfluidic environments.

Main Methods:

• The method relies on the principle that analyte effective mobility (μeff) is constant in a given background electrolyte (BGE).
• Analyte μeff is determined in a reference microchip with known fast EOF.
• Apparent mobility (μapp) is measured in the microchip with unknown low EOF; μEOF is calculated as μapp - μeff.

Main Results:

• Successfully determined low EOF rates in microchip CE.
• Demonstrated the method's applicability to wall-modified microchannels.
• Provided a straightforward calculation for μEOF using μapp and μeff.

Conclusions:

• The developed method offers a quick and effective way to measure low EOF in microchip CE.
• This technique is particularly advantageous for microchannels with suppressed or modified EOF.
• Enables more accurate electrophoretic analyses in microfluidic devices with challenging flow characteristics.