Separation high voltage field driven on-chip amperometric detection in capillary electrophoresis

Area of Science:

• Analytical Chemistry
• Electrochemistry
• Separation Science

Background:

• Amperometric detection in capillary electrophoresis (CE) traditionally requires complex potentiostatic setups.
• Simplifying instrumentation is crucial for developing portable and cost-effective analytical devices.

Purpose of the Study:

• To present a new potentiostatless detection scheme for amperometric detection in CE.
• To investigate the feasibility of using spatial potential differences generated by microband electrodes in a high-voltage CE field for detection.

Main Methods:

• Utilized two gold microband electrodes positioned near the CE capillary outlet.
• Measured the induced potential difference as a function of applied CE separation voltage.
• Investigated the dependence of electrochemically generated current on the high-voltage field and analyte concentration (using Fe(CN)6(4-)/Fe(CN)6(3-)).

Main Results:

• Demonstrated that current generated by the potentiostatless method correlates with CE separation voltage, mirroring cyclic voltammograms from traditional setups.
• Established a proportional relationship between the generated current and the concentration of the redox couple.
• Showcased a simplified instrumental setup by eliminating the need for a decoupling device.

Conclusions:

• The developed potentiostatless amperometric detection scheme for CE is effective and simplifies instrumentation.
• This approach offers a promising pathway for creating inexpensive, portable, chip-based CE devices.