Development of an Extraction Method Based on a Zirconium-based Metal Organic Framework for the Detection and Determination of some Pesticides in Juice Samples Using GC-FID

The proposed analytical method tries to illustrate a new approach for the extraction of some pesticides from different fruit beverages (orange, pineapple, cherry, and mango) using UiO-66 as a capable adsorbent. Further preconcentration for heightening enrichment factors of the analytes was accomplished using a dispersive liquid-liquid microextraction. The synthesized adsorbent was carefully characterized using nitrogen adsorption/desorption, X-ray diffraction, MAP, Fourier transform infrared spectrophotometry, energy dispersive X-ray, and scanning electron microscopy analyses. The performed analyses proved the successful formation of the desired compound. After the sorption of the target compounds onto UiO-66 particles by vortexing, the adsorbent was separated by centrifugation. The analyte-loaded adsorbent was treated with 1.0 ml of acetonitrile for the aim of desorption. The obtained eluate containing the desorbed pesticides was mixed with 38 μl of 1,1,1-trichloroethane and hastily injected into sodium chloride solution. After the centrifugation, an aliquot of the sedimented phase was injected into a gas chromatograph equipped with a flame ionization detector. Satisfactory figures of merit obtained in this survey consisted of high enrichment factors (215-275), acceptable extraction recoveries (43-55%), low limits of detection (1.10- 2.35 μg l-1) and quantification (3.66-7.82 μg l-1), low relative standard deviations (≤ 7.8%), and wide linear ranges. Also, the proposed method benefits from the high surface area of the adsorbent and the low matrix effect.