a green ultrasonic-assisted liquid-liquid microextraction based on deep eutectic solvent for the hplc-uv determination of tbhq in edible oils

A green and inexpensive ultrasonic-assisted liquid-liquid microextraction (uallme) technique based on deep eutectic solvents (dess) was employed in the extraction and separation of tert-butylhydroquinone (tbhq) from edible oils. in a typical experiment, 400 μl des as extraction solvent was added to 3.0 ml sample solution containing 0.15 g edible oil, and then ultrasonic-assisted extraction was applied. after centrifugation, des phase containing tbhq was directly analyzed by reverse phase high-performance liquid chromatograph-ultraviolet detector (hplc-uv) and no phase inversion was involved, which can simplify the sample pretreatment process. under optimized condition, tbhq showed a linear calibration curve in the range of 5∼500 mg/kg (r 2 = 0.9998) and lower limit of detection (lod) of 0.02 μg/ml. the recoveries were in the range of 98.5∼112%, and the intraday and inter-day precision were less than 3.2%. this method was successfully applied to the determination of tbhq in 13 edible oil (e.g., soybean oil, blend oil) samples, which the result was close to that for conventional liquid-liquid extraction with methanol as solvent.