Hydrophobic polymer monoliths as novel phase separators: application in continuous liquid-liquid extraction systems

Area of Science:

• Materials Science
• Analytical Chemistry
• Chemical Engineering

Background:

• Hydrophobic macroporous polymer monoliths offer potential for creating selective solvent gates.
• Tailoring surface chemistry and porous properties is key to achieving selective permeability for organic solvents over water.

Purpose of the Study:

• To evaluate poly(butyl methacrylate-co-ethylene dimethacrylate) (BMA-EDMA) and poly(styrene-co-divinylbenzene) (PS-DVB) monoliths as selective solvent gates.
• To construct and test a phase separator utilizing these monoliths for on-line liquid-liquid extraction (LLE) coupled with gas chromatography (GC).

Main Methods:

• Synthesis and characterization of BMA-EDMA and PS-DVB polymer monoliths with varied chemistries and porosities.
• Breakthrough experiments to assess solvent permeability and pressure requirements.
• Construction of a phase separator and its integration with a chip-based continuous LLE system.
• Evaluation of separation efficiency, flow rate tolerance, and robustness.

Main Results:

• PS-DVB monoliths demonstrated higher hydrophobicity and better flow characteristics for organic solvents compared to water.
• BMA-EDMA monoliths showed efficiency in separating mid-polarity solvents like ethyl acetate from water.
• The constructed phase separator enabled efficient, continuous LLE with segmented flow, achieving good solvent separation across various flow rates and ratios.
• The device exhibited robustness and a long operational lifetime.

Conclusions:

• Hydrophobic polymer monoliths, particularly PS-DVB, are effective materials for selective solvent gates.
• The developed phase separator is suitable for simple, reliable, and continuous LLE applications prior to GC analysis.
• This technology offers a promising approach for on-line sample preparation in analytical chemistry.