Pesticide content analysis of red and yellow watermelon juices through a solid phase microextraction using a green copper-based metal–organic framework synthesized in water followed by a liquid phase microextraction procedure

For the first time, this survey demonstrates the use of MIL-53 (Cu) in an analytical method for the detection and determination of some pesticides through their extraction and preconcentration from red and yellow watermelon juices. The other predominance of the research is using a green metal-organic framework that is based on copper and synthesized in deionized water. After conducting the synthesis process, Fourier transform infrared spectrophotometry, X-ray diffraction, scanning electron microscopy, and nitrogen adsorption/desorption analyses were carried out. In the analytical approach, the samples were accompanied by the sorbent addition and vortexed to facilitate the sorption of the analytes onto the sorbent and then centrifuged to be settled down. Then, the analyte-loaded sorbent particles were treated with mL-volume of acetonitrile and subjected to vortexing and centrifugation. Eventually, the eluate was mixed with μL-level of carbon tetrachloride and instantly injected into deionized water. The resulting milky solution was centrifuged and consequently, the sedimentation of the organic phase occurred at the bottom of the conical glass test tube. An aliquot of it was injected into a gas chromatograph equipped with flame ionization detector. Low limits of detection (0.85-1.24 μg L-1) and quantification (2.80-4.10 μg L-1), high enrichment factors (275-330), and reasonable extraction recoveries (55-66%) were the main achievements of the presented method. It is worthwhile to be confessed that chlorpyrifos was detected in red watermelon juice at a concentration of 27 ± 2 μg L-1.