Development of a gas–controlled deep eutectic solvent–based evaporation–assisted dispersive liquid–liquid microextraction approach for the extraction of pyrethroid pesticides from fruit juices

In current study, a new mode of evaporation–assisted dispersive liquid–liquid microextraction method named as gas–controlled–deep eutectic solvent–based evaporation–assisted dispersive liquid–liquid microextraction has been proposed for the extraction of pyrethroid pesticides from fruit juices prior to their quantification by gas chromatography–mass spectrometry. In the proposed approach, a mixture of choline chloride: butyric acid deep eutectic solvent (as an extractant) and chloroform (as a density modifier) is added to aqueous solution of the analytes placed into a narrow–bore tube. Afterward nitrogen gas is bubbled into the tube through a glass syringe barrel connected to a needle. By this action, chloroform is evaporated and removed from the system and tiny droplets of the extractant are released. The droplets move up through the aqueous phase owing to their low density in comparison with the aqueous phase and the analytes are extracted into them. Several factors which can affect capability of the method were explored. Under final conditions, extraction recoveries and enrichment factors were attained in the ranges of 83–92% and 623–690, respectively. Relative standard deviation at a concentration of 150 ng L^–1 (each analyte) was less than 6.9%. Limits of detection and quantification were in the ranges of 9–21 and 31–69 ng L^–1, respectively. At the end, the offered approach was done on various fruit juice samples marketed in Tabriz city (Iran) and based on the outcomes the studied samples were free of the selected pesticides.