Solid phase microextraction of chlorpyrifos residues in food samples using polyacrylamide@MOF/MXene composite

The excessive use of pesticides in lemon harvesting and goat milk farming leads to harmful organophosphorus residue accumulation, necessitating advanced adsorbents and detection techniques. This study presents a novel method for the detection of chlorpyrifos (CPF) in lemon juice and goat milk using a polyacrylamide@MOF/MXene composite. The composite was thoroughly characterized with Fourier-transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM) and demonstrated a remarkable CPF adsorption efficiency of 99.2 %. The analytical method with limits of detection (LOD) and limits of quantification (LOQ) for lemon juice and goat milk at 1.5 μgL^-1, 2.3 μgL^-1 and 5.1 μgL^-1, 6.9 μgL^-1, respectively showed high accuracy and reliability. Excellent recoveries of 99.2 %, 98.5 % for lemon juice and goat milk, respectively and consistent performance across five adsorption cycles were obtained. Adsorption process was best described by the Freundlich model (R² = 0.993), indicating physisorption, further supported by pseudo-first-order kinetics (χ² = 0.034, R² = 0.994). Precision analysis indicated low relative standard deviations (RSD) of 3.50 % intraday and 3.78 % to 3.85 % interday. The proposed analytical method with its promising performance can open new avenues for pesticide contamination detection in food samples, offering a hopeful outlook for future applications.