Air-assisted liquid-liquid microextraction of total 3-monochloropropane-1,2-diol from refined edible oils based on a natural deep eutectic solvent and its determination by gas chromatography-mass spectrometry

In this paper, a fast, sensitive, and selective sample preparation procedure was presented for the determination of 3-monochloropropane-1,2-diol (3-MCPD) in refined edible oils using gas chromatography-mass spectrometry. In this method, firstly, the sample lipids and analyte fatty esters are saponified by sodium hydroxide under sonication. After that the analyte was derivatized using phenylboronic acid (as the derivatization agent) and the obtained derivative was extracted during an air-assisted liquid-liquid microextraction procedure (AALLME). Six different deep eutectic solvents (DESs) were prepared as the extraction solvents and the most effective extraction for 3-MCPD was obtained in the presence of a natural DES (NDES) consisting of choline chloride (ChCl)-acetic acid (AcOH). Important variables such as sodium hydroxide concentration and volume, sonication time, temperature, extraction solvent type and volume, and phenylboronic acid concentration and volume have been optimized. Using the optimum conditions, broad linear range (0.88-1000 ng g^–1), suitable coefficient of determination (0.995), and low limits of detection (0.26 ng g^–1) and quantification (0.88 ng g⁻¹) were obtained. Relative standard deviations for intra– (n=8) and inter-day (n=6) precisions at a concentration of 5 ng g⁻¹ were 2.6 and 3.2%, respectively. The developed method has been successfully applied to 3-MCPD determination in refined edible oil samples including sunflower, corn, and canola oils.