Application of magnetic benzamide-coated SiC nanocomposite in effervesces-assisted DSPE combined with DLLME for the extraction of pesticides from fruit juice samples

Abstract

In the present study, a magnetic benzamide-coated SiC composite was synthesized, characterized, and used in a dispersive solid phase extraction procedure. The designed method was used for the extraction of mostly used pesticides (permethrin, chlorpyrifos, haloxyfop methyl ester, hexaconazole, pretilachlor, diniconazole, tebuconazole, triticonazole, phosalone, and difenoconazole) from fruit juice samples prior to their determination by gas chromatography-mass spectrometry. In this approach, an effervescent tablet was prepared by pressing a mixture of tartaric acid, sodium bicarbonate, and the synthesized sorbent. Then the tablet was released into the sample solution and the produced carbon dioxide bubbles were used for dispersion of the sorbent particles into the solution. After extraction, the sorbent was collected by an external magnet and the supernatant was discarded. The analytes adsorbed onto the sorbent surface were eluted by acetone. After vortexing and centrifugation, the supernatant was drawn and mixed with carbon tetrachloride and the mixture was dispersed into a sodium chloride solution. Under the optimal conditions, linear ranges of the calibration curves were in the range of 0.53–2000 ng mL−1. The detection limits and precision of the method (expressed as relative standard deviation) were in the ranges of 0.02–0.21 ng mL−1 and 3.1–6.4%, respectively. Finally, the method was done on grape, apple, and orange juices and difenoconazole and chlorpyrifos were found in grape juice at the concentrations of 3.9 ± 0.3 and 1.5 ± 0.1 ng mL−1, respectively.