Molecularly imprinted polymers combination with deep eutectic solvents for solid-phase extraction of caffeic acid...

Area of Science:

• Polymer Chemistry
• Analytical Chemistry
• Natural Product Extraction

Background:

• Caffeic acid is a valuable phenolic compound found in hawthorn with various health benefits.
• Efficient and selective extraction methods are crucial for isolating caffeic acid from complex natural matrices.
• Molecularly imprinted polymers (MIPs) offer tailored recognition sites for specific target molecules.

Purpose of the Study:

• To develop and evaluate molecularly imprinted polymers (MIPs) for the selective solid-phase extraction (SPE) of caffeic acid.
• To investigate the use of deep eutectic solvents (DESs) as effective elution solutions for MIPs-SPE.
• To optimize the MIPs-SPE procedure for enhanced caffeic acid recovery from hawthorn extracts.

Main Methods:

• Preparation of MIPs and non-imprinted polymers (NIPs) using caffeic acid as the template molecule.
• Characterization of MIPs and NIPs using field emission scanning electron microscopy (FE-SEM) and adsorption tests.
• Application of MIPs, NIPs, and C18 for solid-phase extraction (SPE) of caffeic acid from hawthorn.
• Systematic screening of various methanol/DES mixtures as elution solvents to optimize SPE performance.

Main Results:

• MIPs demonstrated significantly higher extraction yields (3.46 µg/g) compared to NIPs (1.01 µg/g) and C18 (1.17 µg/g) for caffeic acid.
• A methanol/glycerol-based DES mixture at a 3:1 (v/v) ratio proved to be the most effective elution solution, achieving an 82.32% recovery rate.
• The optimized MIPs-SPE method showed superior selectivity and efficiency for caffeic acid purification.

Conclusions:

• Molecularly imprinted polymers are highly effective and selective materials for the solid-phase extraction of caffeic acid.
• Deep eutectic solvents, particularly methanol/glycerol mixtures, are promising and tunable elution systems for MIPs-SPE applications.
• The developed MIPs-SPE method offers a robust approach for the efficient isolation of caffeic acid from natural sources like hawthorn.