Analytical application of MIL-53 (Al) for the extraction of pesticides from fruit juices following their preconcentration through dispersive liquid-liquid microextraction

Abstract

For the first time, this study demonstrates an analytical application of MIL-53 (Al) synthesized using Al as the central ion and deionized water as the reaction solvent in mild conditions. The sorbent was used in a dispersive micro solid phase extraction followed by dispersive liquid-liquid microextraction for pesticide content analysis of mango, cherry, pineapple, and orange juices. Different analyses including Fourier transform infrared spectrophotometry, X-ray diffraction, energy dispersive X-ray, scanning electron microscopy, and nitrogen adsorption/desorption techniques were used to characterize the sorbent. Initially, the sorbent was added into the aqueous solution of pesticides and vortexed to facilitate the sorption of the analytes onto the sorbent. After centrifugation, acetonitrile was used to desorb the pesticides from the sorbent surface. Eventually, acetonitrile was mixed with 1,1,1-trichloroethane at µL-level as an extractant and injected into deionized water. An aliquot of the sedimented phase after centrifugation was injected into a gas chromatograph equipped with a flame ionization detector. Satisfactory results were achieved after the optimizations. The results include acceptable extraction recoveries (44-75%), high enrichment factors (220-375), and low limits of detection (0.85-1.85 µg L−1) and quantification (2.80-6.11 µg L−1). Also, little amount utilization of the sorbent and organic solvents and observing no critical matrix effect are the priorities of the method.