Volatile free liquid membranes for electromembrane extraction

Area of Science:

• Analytical Chemistry
• Separation Science
• Electrochemistry

Background:

• Volatile solvents are typically avoided in supported liquid membranes (SLMs) due to evaporation and instability.
• Electromembrane extraction (EME) has not previously utilized volatile solvents effectively.
• Supported liquid membranes (SLMs) face limitations with volatile solvents, hindering their application in electromembrane extraction (EME).

Purpose of the Study:

• To investigate the potential of volatile solvents as free liquid membranes (FLMs) in electromembrane extraction (EME).
• To comprehensively examine the extraction characteristics and stability of volatile FLMs in EME.
• To demonstrate the application of volatile FLMs for the extraction of model drugs from biological matrices.

Main Methods:

• Utilized a micro-electromembrane extraction (μ-EME) setup with volatile solvents as free liquid membranes (FLMs).
• Employed ethyl acetate and chloroform as volatile FLMs for extracting model basic drugs (nortriptyline, haloperidol, loperamide, papaverine) and atenolol.
• Analyzed extracts using capillary electrophoresis with ultraviolet detection (CE/UV).

Main Results:

• Volatile FLMs demonstrated excellent stability and comparable or superior extraction performance to non-volatile solvents.
• High extraction recoveries (62%-99% for standards, 40-89% for body fluids) and selectivity were achieved.
• The μ-EME-CE/UV method showed excellent repeatability (RSD 0.8-3.2% intra-day, 1.8-4.6% inter-day) and suitability for raw biological fluids.

Conclusions:

• Volatile solvents can be effectively used as free liquid membranes (FLMs) in electromembrane extraction (EME), overcoming previous stability limitations.
• This approach broadens the scope of solvents for EME and offers a stable, efficient method for drug analysis.
• The study provides a proof-of-concept for volatile FLMs in EME, paving the way for further research into volatile phase interfaces.