Selective solid phase extraction of phototoxic furanocoumarins using molecularly imprinted polymers

Furanocoumarins are secondary plant metabolites found in citrus plants. Essential oils from these plants are widely used in cosmetic products. They have attracted attention for their phototoxicity, which can even lead to skin burns. Therefore, the furanocoumarin concentration is controlled by the European Union according to Regulation (EC) No. 1223/2009, where a limit of 1 mg kg−1 is specified in sun protection and bronzing agents. This study describes the synthesis of two molecularly imprinted polymers (methacrylamide and methacrylic acid as monomers) as novel materials for solid phase extraction. After optimisation of the extraction protocol, both polymers gave satisfying recovery results for a furanocoumarin standard mixture containing the six markers proposed by the International Fragrance Association (IFRA). Furthermore, spiked sun oil samples were extracted using an adapted extraction protocol. Since the studies showed promising results including 75-149% recovery and 100% loading efficiency for the methacrylic acid polymer, a validation of the analytical method was performed. Analysis was performed using HPLC-MS/MS in high specificity multi-reaction monitoring mode. The validation showed acceptable results for most parameters. In addition, a comparison with commercially available Strata-X cartridges was completed, revealing superior recovery performance of the molecularly imprinted polymer. In conclusion, molecularly imprinted polymers represent a novel and efficient method for selective solid-phase extraction of phototoxic furanocoumarins.