A novel, green and safe ultrasound-assisted emulsification liquid phase microextraction based on alcohol-based deep eutectic solvent for determination of patulin in fruit juices by spectrophotometry

In the study, a novel, green and safe microextraction procedure was developed for the determination and extraction of patulin, alpha,beta-unsaturated lactone (4-hydroxy-4H-furo[3,2-c] pyran-2-(6H)-one), in fruit juice samples by using ultrasound-assisted emulsification liquid phase microextraction based on alcohol-based deep eutectic solvent coupled to micro-volume ultraviolet-visible spectrophotometry. The method is based on formation of chelate complex or nucleophilic adduct formation between patulin and Mg(II) in presence of nucleophilic metal chelating tris-buffer at pH 8.0, and then extraction of the formed complex into the micro-drops of deep eutectic solvent by donor-acceptor mechanism. The optimum conditions for the effective extraction of patulin from fruit juices were 500 mu L of deep eutectic solvent, 75 mu mol L-1 of Mg(II) solution, pH 8.0, ultrasound time of 12 min, respectively. The patulin in enriched phase was detected by micro-volume ultraviolet-visible spectrophotometry at 304 nm. Under optimal conditions, the linear response range of the method was from 7.5 to 420 mu g L-1 with a detection limit of 2.2 mu g L-1. After the validation study, the applicability of the method were tested by analysis of the fruit juice samples. The average recovery for spiked fruit juices was ranged from 90.2% to 106.9%, with relative standard deviations lower than 4.2%.