Development of deep eutectic solvent based pressurized liquid extraction combined with dispersive liquid–liquid microextraction; application in extraction of aflatoxins from rice samples before HPLC–FLD

Abstract

In the current study, a sample pretreatment based on the combination of deep eutectic solvent–based miniaturized pressurized liquid extraction and deep eutectic solvent–based dispersive liquid–liquid microextraction has been introduced. The offered approach was applied for extraction and preconcentration of aflatoxins from rice samples prior to their determination by high performance liquid chromatography–fluorescent detector. For this purpose, first, the analytes were extracted from solid sample matrix into a water–miscible deep eutectic solvent at elevated temperature and pressure. Then, the supernatant phase was taken and mixed with water–immiscible deep eutectic solvent. This mixture was hastily injected into deionized water and consequently a cloudy state was appeared. In the following, the obtained mixture was centrifuged and the sedimented phase was injected into separation system after diluting with acetonitrile. Acceptable results such as low limits of detection (0.02–0.07 ng g−1) and quantification (0.07–0.23 ng g−1), and high extraction recoveries (69–82%) were obtained. Toward the end, the recommended method was applied for the quantification of the aflatoxins in different rice samples.