Synthesis of Polyoxometalates-Ionic Liquids@Fe₃O₄@SiO₂ composites for the extraction of atrazine and deltamethrin pesticides residues from food samples and their determination by HPLC

The excessive use of pesticides in food production has adverse effects on both the environment and human health. In the present study, atrazine and deltamethrin were employed as pesticides in the cultivation of tomatoes, cucumbers, and brinjal. The HPLC method was utilized for thesimultaneous determination of these two pesticides, employing a cleanup approach based on polyoxometalates (POMs)ionic liquids magnetic nanocompositesCuILPOM-Fe3O4@SiO2 and ZnILPOM-Fe3O4@SiO2. These magnetic nanocomposites were synthesized and subjected to comprehensive characterization using various analytical techniques, including fourier-transform infrared spectroscopy(FT-IR), UV–visible spectroscopy, powder X-ray diffraction(P-XRD),transmission electron microscope(TEM),scanning electron microscopy (SEM) and energy dispersive X-rays spectroscopy (EDX),thermogravimetric analysis (TGA), and rheology. Thedispersive solid-phase extraction (d-SPE) method was effectively employed for the extraction of pesticidesresidues using CuILPOM-Fe₃O₄@SiO₂ and ZnILPOM-Fe₃O₄@SiO₂. Under the optimized conditions, the linear concentration ranges for atrazine and deltamethrin were found to be 0.01–100.0 µg/L and 0.05–100 µg/L, respectively. The coefficient of determination (R²) for both compounds was notably high at 0.997 and 0.994, respectively. The limit of detection (LOD) ranged from 0.01 µg/L to 0.05 µg/L, and the relative standard deviations (RSDs) fell within the range of 5.1 % to 7.2 %. Ultimately, the method's performance in various food samples was assessed, resulting in satisfactory recoveries ranging from 80.9 % to 98.6 %.