UIO-66-NH2 encapsulated polyoxometalate loaded on graphene oxide accommodated on mixed cellulose esters (MCE) paper for thin film microextraction of pesticides besides their quantification via high-performance liquid chromatography-ultraviolet detection

A POM@UIO-66-NH2/GO composite was designed and prepared via a facile in-situ synthesis method for microextraction purposes. The proper sizes (window size and pore size) of UIO-66-NH2 can effectively seal POM as a monomolecular active component and prevent POM leaching during the extraction. After that, a membrane containing POM@UIO-66-NH2/GO nanocomposite was synthesized and utilized in thin film microextraction (TFME) of various pesticides such as imidacloprid, tebuconazole, and propiconazole as the model analytes in different real samples such as cucumber, tomato, potato, head lettuce, and strawberry. It is worth mentioning that the introduction of GO can improve the electron transfer of the sorbent. The extracted model analytes were desorbed by a suitable organic solvent. The extracted analytes were quantified via high-performance liquid chromatography-ultraviolet detection (HPLC-UV). Under the optimized condition, the method's linear dynamic range (LDR) was obtained in the range of 1.0–200.0 μg L−1 for testing analytes. The obtained correlation coefficients (r2) were higher than 0.9918. The limits of detection (LODs) were also calculated to be between 0.31 and 0.34 μg L−1. The relative standard deviations (%RSDs) were obtained in the range of 2.06 to 4.11. The enrichment factor (EF) values for the studied analytes were also obtained in the range of 89–102. The obtained recoveries indicated that the presented method is useful for analyzing pesticides in various real samples.