Molecularly Imprinted Solid Phase Extraction Strategy for Quinic Acid.

Area of Science:

• Analytical Chemistry
• Polymer Science
• Food Chemistry

Background:

• Quinic acid (QA) and its ester conjugates are investigated for antioxidant properties.
• Selective extraction of QA from complex matrices like coffee is challenging.
• Molecularly imprinted polymers (MIPs) offer potential for specific analyte recognition.

Purpose of the Study:

• To develop and optimize molecularly imprinted polymers (MIPs) for the selective extraction of quinic acid (QA).
• To apply the developed MIPs for solid-phase extraction (SPE) of QA from coffee bean extract.
• To evaluate the selectivity and efficiency of the MIP-based extraction method.

Main Methods:

• Computational modeling was used to optimize MIP preparation parameters.
• Three functional monomers (allylamine, methacrylic acid, 4-vinylpyridine) were tested for imprinting QA.
• Equilibrium rebinding studies identified the optimal MIP formulation (MIP C using 4-VP).
• Molecularly imprinted solid-phase extraction (MISPE) was performed using MIP C as the sorbent.

Main Results:

• MIP C, prepared with 4-vinylpyridine at a 1:5 template-to-monomer ratio, exhibited superior binding performance.
• MIP C demonstrated selectivity for QA over its coffee analogues, caffeic acid and chlorogenic acid.
• The MISPE method using MIP C successfully extracted 81.918 ± 3.027% of QA from aqueous coffee extract.
• A significant reduction in co-extracted interfering compounds was observed.

Conclusions:

• Optimized MIPs, particularly MIP C, are effective for the selective extraction of quinic acid.
• MISPE using MIP C provides an efficient and selective method for isolating QA from coffee.
• This technique facilitates the analysis of QA and its antioxidant properties in complex food matrices.