Development of dispersive solid phase extraction based on carbon nano-onions sorbents and its application in extraction of some widely used pesticides from fruits and vegetable samples prior to their determination by gas chromatography-flame ionization detector

Abstract

Introduction: In this method, a DSPE procedure in combination with DLLME has been used for the extraction and preconcentration of some pesticides in various fruit and vegetables. CNOs were used as the sorbent in the DSPE step. Expression of purpose: The main goal of this work was the development of the DSPE method with CNOs–based sorbents for the extraction of several pesticides related to different classes from fruit and vegetable samples.Method: In the proposed method, 100 mg level of CNO was added into 5 mL aqueous solution containing the analytes. After dispersing by vortex, an appropriate organic solvent (aceton) was used for desorption of the analytes from the sorbent. To obtain high enrichment factors, the eluate was mixed with carbon tetrachloride at 35µL level and DLLME method is done. After centrifugation of the obtained cloudy solution, fine droplets of the extraction solvent were collected at the bottom of the tube. Finally, 1 µL of the sedimented organic phase was injected into the GC-FID system for analysis.Results: EFs and ERs were in the ranges of 350-410 and 70-82%, espectively. LOQs and LODs were in the ranges of 1.8-5.4 ng g-1 and, 0.5-1.6 ng g-1 respectively. RSDs for extraction of the selected pesticides were (≤7.2%).Discussion and conclusion: In this method, for the first time, a disperser solvent was simultaneously used as a derivatization agent in DLLME. Under the optimum conditions, the obtained data indicated that the method has low LODs and LOQs, high EFs and ERs, and short extraction time.