Simultaneous determination of imidacloprid and diazinon in apple and pear samples using sonication and dispersive liquid-liquid microextraction

The combination of sonication and dispersive liquid-liquid microextraction based on the solidification of floating organic drop (SDLLME-SFO) has been developed for extraction and determination of imidacloprid and diazinon from apple and pear samples. Target 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, extraction recoveries for different fruits are in the range of 58-67%. The calibration graphs are linear in the range of 3-600 mu g kg(-1) and limit of detections (LODs) are in the range of 1-2 mu g kg(-1). Repeatability (intra-day) and reproducibility (inter-day) of method based on five replicate measurements of 100 mu g kg(-1) of pesticides were in the range of 4.3-5.2% and 5.5-6.8%, respectively. Finally, the proposed method was applied with satisfactory results to the analysis of these pesticides in apple and pear samples that were collected from eight different gardens. The results showed that DLLME-SFO is a very simple, rapid, sensitive and efficient analytical method for the determination of trace amount of pesticides in fruit samples and suitable results were obtained. (C) 2014 Elsevier Ltd. All rights reserved.