Electrochromatography in poly(dimethyl)siloxane microchips using organic monolithic stationary phases.

Area of Science:

• Analytical Chemistry
• Materials Science
• Microfluidics

Background:

• Polydimethylsiloxane (PDMS) is widely used in microfluidic devices but can absorb organic monomers, complicating in situ synthesis of stationary phases.
• Developing robust stationary phases within PDMS microchannels is crucial for advancing on-chip separation techniques like electrochromatography.

Purpose of the Study:

• To demonstrate the in situ synthesis of a hexyl acrylate monolith within PDMS microfluidic devices.
• To overcome PDMS monomer absorption issues through surface modification.
• To utilize the synthesized monolith as a stationary phase for on-chip electrochromatography.

Main Methods:

• Surface modification of PDMS microchannels via UV-mediated graft polymerization using a photoinitiator.
• In situ casting of hexyl acrylate monoliths through photopolymerization.
• Electrochromatographic separation of derivatized catecholamines in the fabricated PDMS device.

Main Results:

• Successful surface modification of PDMS channels to prevent monomer absorption.
• In situ synthesis of hexyl acrylate monoliths within microfluidic devices.
• Achieved efficient separation of derivatized catecholamines with high column efficiencies (up to 200,000 plates/meter).

Conclusions:

• The developed method enables robust in situ synthesis of monolithic stationary phases in PDMS microfluidic devices.
• This approach is effective for on-chip electrochromatography, offering high separation efficiencies.
• The technique holds promise for miniaturized analytical systems requiring integrated separation capabilities.