Graphene-Modified Magnetic Nanoparticles for Analyzing Some Pesticides Through Magnetic Dispersive Solid Phase Extraction and Dispersive Liquid-Liquid Microextraction Followed by GC-MS Determination

In this study, an efficient magnetic sorbent was prepared to extract some pesticides including chlorpyrifos, haloxyfop-R-methyl, oxadiazon, diniconazole, clodinafop-propargyl, fenpropathrin, and fenoxprop-P-ethyl. Magnetic Fe3O4 nanoparticles were coated with graphene as a sorbent for the extraction of the target compounds in some fruit juices. The synthesized sorbent was characterized by vibrating sample magnetometery, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer-Emmett-Teller nitrogen sorption, Fourier transform infrared spectroscopy, and X-ray diffraction. First, the studied pesticides were adsorbed on the sorbent from a solution containing dissolved Na2SO4. In the following, the analytes were desorbed from the sorbent by 2-propanol. Then, the eluent containing analytes was separated from the sorbent, mixed with 1,1,2-trichloroethane (at mu L level), and injected into a solution containing dissolved NaCl. After centrifuging the formed cloudy solution, an aliquot of the sedimented phase was injected into a gas chromatograph equipped with mass spectrometer. The method has satisfactory extraction recoveries (42-76%), high enrichment factors (155-362), and good linearities of the calibration curves (r(2) >= 0.992). Limits of detection and quantification were in the ranges of 0.04-0.06 and 0.13-0.19 ng mL(-1), respectively. The proposed method was applied in the analysis of the selected pesticides in different fruit juices and fenpropathrin was found in mango juice at 17 +/- 0.1 ng mL(-1) level concentration.

Automated summary

In this study, an efficient magnetic sorbent was prepared and applied for the extraction of pesticides from fruit juices. The proposed method showed satisfactory extraction recoveries, high enrichment factors, and good linearities. It can be used for the analysis of pesticides in different fruit juices.