Efficient and Sensitive Detection of Organophosphate Pesticides in Orange Juice Using Dispersed Solid-Phase Extraction Based on Amorphous UiO-66

Organophosphate pesticides can cause long-term neurological damage to humans. There is an urgent need to develop a more sensitive and efficient method for detecting trace amounts of organophosphorus pesticides in orange juice, particularly in the presence of interfering substances. This study developed a dispersive solid-phase extraction (DSPE) method using amorphous UiO-66 (aUiO-66) as an adsorbent for the detection of four organophosphate pesticides (fenthion, profenofos, fensulfothion, and chlorpyrifos) in orange juice. The aUiO-66 was synthesized in a green, direct method within a deep eutectic solvent composed of diethanolamine hydrochloride and acetamide. Its amorphous nature was confirmed through x-ray diffraction (XRD) and thermogravimetric analysis (TGA). Parameters influencing extraction efficiency, including adsorbent dosage, extraction time, eluent type, and volume, were optimized by genetic neural network (GNN). The method demonstrated good linearity (R² = 0.9927–0.9981), high recovery (95.35%–110.75%), low limit of detection (0.169–0.214 ng L⁻¹), and precision (intraday RSD = 4.13%–5.44%, interday RSD = 3.28%–4.91%). It was successfully applied to analyze targets in commercially available orange juices, detecting residues within 4.37–36.07 µg L⁻¹. This study's methodological development offers significant guidance for efficient detection of organophosphorus pesticides in food products, potentially facilitating the advancement and application of simpler and more efficient analytical techniques.