A highly efficient microextraction technique based on deep eutectic solvent formed by choline chloride and p-cresol for simultaneous determination of lignans in sesame oils

For simultaneous determination of lignans (i.e. sesamin, sesamolin and sesamol) in sesame oils, a highly efficient ultrasonic-assisted liquid-liquid microextraction (UALLME) technique was developed based on deep eutectic solvents (DESs) composed of choline chloride and p-cresol. Compared with the common polyols-based DESs (i.e. choline chloride-ethylene glycol), the phenolic DESs exhibited higher extraction efficiency for both polar lignans (i.e. sesamol) and non-polar lignans (i.e. sesamin and sesamolin) due to the p-p interaction between lignans and DES. After the UALLME process, DES phase was analyzed by HPLC-UV. Under optimized condition, all three lignans showed good linear calibration curves and low limit of detection. The recoveries were in the range of 97.3-120%, and the intra-day and inter-day precisions were less than 0.97%. Moreover, this method was used for simultaneous determination of lignans in 15 commercial oil samples. The results showed that the new microextraction technique achieved similar efficiency as the conventional liquid-liquid extraction method.