AlFu nano MOF-based dispersive micro solid phase extraction of pesticides; the comparison of preconcentration via evaporation and dispersive liquid–liquid microextraction

Abstract

ABSTRACT For the first time in this research, a nano AlFu metal-organic framework (MOF) was exploited for the extraction of some pesticides (fenitrothion, haloxyfop-R-methyl, hexaconazole, oxadiazon, diniconazole, and clodinafop-propargyl) from different beverage samples (cherry, orange, mango, and peach juices). A comparative study was also accomplished for the evaluation of the preconcentration efficiency through the applied method in this study (gas-assisted evaporation) and conventional dispersive liquid–liquid microextraction (DLLME). Essential characterisations including X-ray diffraction, Fourier transform infrared spectrophotometry, Brunauer–Emmett–Teller, energy-dispersive X-ray, and scanning electron microscopy were conducted on the nano adsorbent. The food safety analysis process was done through the dispersion of the nano adsorbent into the Na2SO4 dissolved sample solution containing the pesticides. After the adsorption of the target compounds, by implementing centrifugation, the sorbent was isolated from the solution. Acetonitrile was used for the elution of the nanoparticles. Analyte-containing acetonitrile phase was evaporated completely in a conical bottom test tube, and its inner perimeter was eluted using a µL-level of 1,2-dibromoethane. An aliquot of the organic phase was injected into the gas chromatograph equipped with a flame ionisation detector. Only 10 mg of the nano adsorbent was used in the procedure due to its high surface area (1067.7 m2 g−1) and porosity (0.9499 cm3 g−1). High enrichment factors (355–480) and extraction recoveries (71–96%) were found. Relative standard deviations in the range of 3.6–4.8% for intra- (n = 5) and 4.3–5.5% for inter-day (n = 3) precisions, and low limits of detection (0.84–1.75 µg L−1) and quantification (2.77–5.77 µg L−1) were also the results of the developed analytical method. Application of AlFu nano MOF for the first time, its low amount utilisation, and superseding evaporation instead of DLLME are the novelty aspects of the research. Abbreviations: DLLME: Dispersive liquid–liquid microextraction; DSPE: Dispersive solid-phase extraction; DµSPE: Dispersive micro-solid-phase extraction; EF: Enrichment factor; FID: Flame ionisation detector; GC: Gas chromatography; LOD: Limit of detection; LOQ: Limit of quantification; LR: Linear range; RSD: Relative standard deviation