Advanced solid phase extraction using molecularly imprinted polymers for the determination of quercetin in red wine.

Solid phase extraction (SPE) based on molecularly imprinted polymers (MIPs) is a novel approach for sample preparation and preconcentration, gaining increased interest in the fields of environmental, clinical, and food analysis. The first application combining MIPs with SPE for advanced beverage analysis is reported. MIPs for the flavonoid quercetin have been generated, using quercetin as a template molecule in a self-assembly approach and yielding imprinting of 1% of the used template. The MIP achieved a capacity of 0.4 g quercetin per gram polymer and a recovery rate of 98.2%. The application of these synthetic receptors as SPE material for the selective extraction and preconcentration of quercetin from synthetic and red wine samples was investigated. Red wine samples from a French Merlot were directly applied onto the SPE cartridge. The collected fractions were analyzed by high-pressure liquid chromatography. For verification of the obtained results, a similarly prepared nonimprinted polymer and a classical octadecyl silane reversed-phase cartridge were applied as the SPE matrix during control experiments. The MIP enabled the selective extraction of quercetin from a complex matrix, such as red wine, spiked with 8.8 mg per liter quercetin, demonstrating the potential of molecularly imprinted solid phase extraction for rapid, selective, and cost-effective sample pretreatment.