Pillar Array Mixer for Postcolumn Derivatization Integrated into Liquid Chromatography-Based Microfluidic Device

Area of Science:

• Analytical Chemistry
• Microfluidics
• Biotechnology

Background:

• Chemical derivatization is crucial for enhancing sensitivity and selectivity in metabolite analysis using microfluidic devices.
• Integrating derivatization units into microfluidic chromatography systems presents significant development challenges.

Purpose of the Study:

• To develop a novel microfluidic derivatization unit for on-chip liquid chromatography (LC).
• To enhance mixing efficiency for post-column derivatization using a pillar array (PA) mixer.
• To demonstrate the device's capability for rapid metabolite analysis.

Main Methods:

• Fabrication of microfluidic devices with an integrated LC column and PA mixer on a silicon plate.
• Utilized computational fluid dynamics (CFD) for concept validation.
• Performed fluid experiments comparing PA mixers with hollow-channel mixers.
• Analyzed amino acids using hydrophilic interaction chromatography (HILIC) coupled with post-column derivatization and fluorescence detection.

Main Results:

• The PA mixer effectively enhanced transverse mixing of derivatization reagents and analytes.
• Analyte peak width was not increased by the PA mixer, preserving separation efficiency.
• Achieved rapid analysis of three amino acids within 40 seconds.
• Demonstrated successful post-column fluorogenic derivatization using naphthalene-2,3-dicarboxaldehyde.

Conclusions:

• The developed PA mixer is effective for post-column derivatization in microfluidic LC systems.
• Integrated derivatization units show significant potential for creating advanced micrototal analysis systems (µTAS).
• This approach facilitates sensitive and selective bioanalysis with high throughput.