Integrating Internal Standards into Disposable Capillary Electrophoresis Devices To Improve Quantification

Area of Science:

• Analytical Chemistry
• Separation Science
• Microfluidics

Background:

• Microchip capillary electrophoresis (MCE) offers potential for point-of-care quantification.
• Chip-to-chip variability in disposable MCE devices hinders accurate results.
• Traditional internal standard (ISTD) methods require complex sample manipulation.

Purpose of the Study:

• To develop a simplified method for improving quantification accuracy in disposable MCE devices.
• To evaluate the effectiveness of integrating ISTDs into the background electrolyte (BGE).
• To compare the performance of integrated ISTDs against traditional ISTD methods.

Main Methods:

• Integrated Cs and Li ions as ISTDs directly into the BGE of MCE microchips.
• Quantified Na using the MCE system with integrated ISTDs.
• Compared reproducibility results with previous studies using traditional ISTD methods.

Main Results:

• Integrated ISTDs (Cs and Li) improved Na peak area reproducibility approximately 2-fold (RSDs of 2.2-4.7%).
• Traditional Cs ISTD yielded RSDs of 2.5-8.8%, while traditional Li ISTD showed RSDs of 6.3-14.2%.
• The integrated ISTD approach provided matched or superior precision compared to traditional methods.

Conclusions:

• Integrating ISTDs into the BGE is a viable strategy to enhance precision in disposable MCE devices.
• This approach eliminates the need for additional sample preparation or system modifications.
• The proposed method offers improved reproducibility without increasing system cost or complexity.