| In the present research, a sample preparation method called dispersive microsolid phase extraction followed by dispersive
liquid–liquid microextraction was developed based on MOF-70 as a highly efficient adsorbent for the extraction of seven
pesticides including chlorpyrifos, haloxyfop-R-methyl, oxadiazon, diniconazole, clodinafop-propargyl, fenpropathrin, and
fenoxaprop-P-ethyl from various fruit beverages (orange, pineapple, pomegranate, grape, and cherry beverages). In the
first step, the pesticides are loaded on the MOF particles from the sample solution by vortexing and then settled down by
centrifugation. Then, they are desorbed by acetonitrile from the MOF surface. In the next step, the obtained acetonitrile
phase is mixed with μL-level of 1,1,1-trichloroethane and injected into deionized water. After the final centrifugation, the
sedimented phase is collected and an aliquot of the obtained phase is injected into a gas chromatograph equipped with a flame
ionization detector. MOF-70 is carefully synthesized and characterized using X-ray diffraction, Fourier transform infrared
spectrophotometry, scanning electron microscopy, energy-dispersive X-ray, and nitrogen adsorption/desorption analysis.
After optimization of the process, satisfactory figures of merit were obtained such as high extraction recoveries (35–96%) and
enrichment factors (175–480), low relative standard deviations (4.5–8.5%), wide linear ranges, and low limits of detection
(0.20–0.76 μg L−
1) and quantification (0.65–2.47 μg L−
1). The developed approach can be introduced as a highly efficient
analytical method based on MOF-70 for the analysis of various pesticides in juice samples. |