Novel ionic liquid based dispersive liquid-liquid microextraction for the extraction of bergapten and bergamottin in hydroalcoholic cosmetic formulations.

This study reports the synthesis of the room temperature ionic liquid 1-propyloxy-3-ethoxyimidazolium bis(trifluoromethane)sulfonamide for the extraction of bergapten and bergamottin from hydroalcoholic cosmetic samples by means of dispersive liquid-liquid microextraction. Molecular structures of the final ionic liquid as well as intermediate products were confirmed by nuclear magnetic resonance spectroscopy. Analyses were performed with high performance liquid chromatography with subsequent diode array and fluorescence detection. The extraction procedure was optimized with the design of the experiment using a three level Box-Behnken approach. Applying the synthesized room temperature ionic liquid as extraction medium, the optimized workflow demonstrated high recoveries illustrating powerful isolation properties for furanocoumarins, which are comparable or even better than using typical extraction solvents. Moreover, the workflow was validated regarding instrumental limits, linearity, accuracy, repeatability and stability of analytes according to international guidelines. To test its applicability on a more complex matrix, hydroalcoholic cosmetic samples were analyzed. Despite highly complex matrices, accurate and precise quantification in the range of 0.04-1.25 μg mL-1 was achieved in spiked and unspiked samples, with bias <10% and RSD < 12%.