Electromembrane extraction from aqueous samples containing polar organic solvents

Area of Science:

• Analytical Chemistry
• Separation Science

Background:

• Electromembrane extraction (EME) is a sample preparation technique.
• Analyzing basic drugs in complex matrices often requires efficient extraction methods.

Purpose of the Study:

• To evaluate the effectiveness of EME for aqueous samples containing various organic solvents.
• To assess the impact of different organic solvents on EME performance and stability.
• To determine optimal conditions for EME with challenging sample matrices.

Main Methods:

• EME was performed using various organic solvents (methanol, ethanol, DMSO, acetonitrile) in aqueous samples.
• Basic drugs (pethidine, haloperidol, nortriptyline, methadone, loperamide) were used as model analytes.
• High-performance liquid chromatography (HPLC) with UV and MS detection was employed for analysis.

Main Results:

• High recoveries (83-95%) were achieved from aqueous samples within 5-10 minutes.
• Comparable recoveries were maintained with 50% methanol, ethanol, or DMSO, though extraction time increased.
• A stable EME system was obtained with 2-nitrophenyl octyl ether (NPOE) as the supported liquid membrane (SLM) for up to 75% DMSO.
• Acetonitrile destabilized the SLM and caused volume expansion, while other SLMs were less effective than NPOE.
• Successful application was demonstrated on dried blood spot extracts (80% methanol).

Conclusions:

• EME is a robust technique for preparing aqueous samples containing significant concentrations of organic solvents.
• NPOE is a suitable SLM for EME in the presence of methanol, ethanol, and DMSO.
• EME offers an effective and efficient sample preparation strategy for challenging matrices.