Selective three-phase liquid phase microextraction of acidic compounds from foodstuff simulants

Area of Science:

• Analytical Chemistry
• Separation Science

Background:

• Aromatic carboxylic acids and phenolic compounds are prevalent in various matrices, necessitating selective extraction methods.
• Existing microextraction techniques may lack the required selectivity or efficiency for complex samples.

Purpose of the Study:

• To develop and optimize a three-phase liquid phase microextraction (LPME) technique for selective extraction of aromatic carboxylic acids and phenolic compounds.
• To evaluate different organic phases and donor phase compositions for optimal extraction efficiency.

Main Methods:

• A three-phase LPME system was designed with acidified donor, organic solvent layer within hollow fiber pores, and alkaline acceptor phases.
• Capillary electrophoresis with UV detection was employed for analyzing extracted compounds.
• Various organic solvents (chloropentane, 2-octanone, AS4 silicone oil) and donor phase additives (ethanol, acetic acid) were tested.

Main Results:

• Chloropentane achieved 73.8%-93.8% recovery for phenols (eugenol, thymol, carvacrol).
• 2-octanone showed 60.7%-93.7% recovery for aromatic carboxylic acids but not phenols.
• AS4 silicone oil proved optimal for phenol extraction in 3% acetic acid and high-alcohol matrices.

Conclusions:

• The developed three-phase LPME technique offers high selectivity for target analytes.
• Choice of organic phase is critical for differentiating between aromatic carboxylic acids and phenols.
• The method shows promise for analyzing phenols in complex matrices like food simulants.