Determination of organophosphorous pesticides in summer crops using ultrasound-assisted solvent extraction followed by dispersive liquid-liquid microextraction based on the solidification of floating organic drop

•Combination of USAE-DLLME-SFO was used for determination of OPPs in summer crops.•The new method avoided using high density and toxic extraction solvents.•Extraction time in DLLME stage is short relative to the other methods.•The method provides good repeatability and high extraction recovery.•No clean-up or evaporation were required after extraction.

The ultrasound-assisted solvent extraction (UASE) followed by dispersive liquid-liquid microextraction based on the solidification of floating organic drop (DLLME-SFO) has been developed for extraction and determination of organophosphorous pesticides from summer crops. Organophosphorous pesticides were determined by high performance liquid-liquid chromatography-ultraviolet detector (HPLC-UV). Some effective parameters on extraction were studied and optimized. Under the optimum conditions, recoveries for different fruits are in the range of 44.0-61.0%. The calibration graphs are linear in the range of 5-800 μg kg−1 and limit of detections (LODs) are in the range of 1-4 μg kg−1. The relative standard deviations (RSDs) for 100 μg kg−1 of OPPs in different fruits are in the range of 5.5-9.1 (n = 5). The obtained results show that UASE-DLLME-SFO combined with HPLC-UV is a fast and simple method for the determination of pesticides in summer crops.