determination of migrated phthalic acid residues into edible oils using a green mode of air-assisted liquid–liquid microextraction followed by high-performance liquid chromatography–diode array detector

In this study, for the first time, an organic solvent-free air-assisted liquid–liquid microextraction method has been reported for the extraction and preconcentration of phthalic acids (o-phthalic acid, m-phthalic acid, and p-phthalic acid) from edible oil samples. the method is based on the repeated aspirating/injection of an alkaline aqueous solution and the oil sample mixture in a conical bottom centrifuge tube to form a cloudy solution. after phase separation by centrifuging, the sedimented phase is directly analyzed by high-performance liquid chromatography–diode array detection. under the optimum extraction conditions, the method showed low limits of detection and quantification between 0.11–0.29 and 0.28–0.91 ng ml−1, respectively. extraction recoveries and enrichment factors were from 81 to 97% and 406 to 489, respectively. the relative standard deviations for the analysis of 5 ng ml−1 of each analyte were less than 5.9% for intraday (n = 6) and interday (n = 5) precisions. finally, different oil samples were successfully analyzed using the proposed method and m-phthalic acid, and p-phthalic acid were determined in some of them at ng ml−1 level.