Preconcentration and GC–MS determination of organochlorine pesticides in fruits and vegetables using eco-friendly magnetic micro-solid phase extraction with deep eutectic solvent-modified magnetic graphene oxide

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Abstract

The current study employed a green urea-based deep eutectic solvent (DES) modified magnetic graphene oxide as a sorbent to pre-concentrate organochlorine pesticides (OCPs) in fruits and vegetables. Subsequently, the samples were subjected to GC-MS analysis. The optimized magnetic micro-solid phase extraction (M-µ-SPE) and GC-MS conditions resulted in linear and matrix-matched calibrations within the 0.01 µg/kg to 500 µg/kg range with a determination coefficient (r²) ≥ 0.9980. Based on the 3 and 10 signal-to-noise ratios, the detection and quantification limits were determined to be 0.003 µg/kg to 0.03 µg/kg and 0.01 µg/kg to 0.1 µg/kg, respectively. The spiked OCPs in the samples also recorded relative recoveries between 87.7 % and 118.5 % at three concentration levels (0.5, 10, and 300 µg/kg) with relative standard deviations of ≤ 6.8 %. The proposed method detected seven OCPs in apples, watermelon, spinach, enoki mushrooms, cabbage, cucumbers, and green bok choy. The OCPs were detected in 15 samples.