Application of MNPs/ODA-SBA-15 composites in pretreatment of organophosphorus pesticide residues in green leafy vegetables

The self-developed magnetic nanoparticles supported octadecane amine-functionalized mesoporous carbon composite was synthesized in this work. A sample pretreatment method for rapid detection of organophosphorus pesticide residues in green leafy vegetables was investigated based on QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) technology and gas chromatography-mass spectrometry. The surface structure of the magnetic mesoporous composite was characterized by transmission electron microscopy and a magnetometer. The experimental results show that the magnetic mesoporous material can eliminate the matrix interference, improve the detection efficiency and simplify the operation compared with the traditional purification agent. The residues of 16 organophosphorus pesticides in green leafy vegetable matrix have a good linear relationship in the concentration range of 0.02–0.25 µg/mL, and the correlation coefficient (R²) is between 0.9943–0.9997. At the addition levels of 0.02, 0.05 and 0.10 mg/kg, the average recovery rate of 16 organophosphorus pesticides in green leafy vegetable matrix is between 81.3–94.0%, the relative standard deviation is less than 10%, and the minimum detection limit is 0.01–0.08 µg/mL. The results showed that all green leafy vegetables met the maximum residue limit of organophosphorus pesticides. This method has the advantages of high sensitivity, strong universality, high accuracy, good stability, financial and economic. It is suitable for detecting pesticide residues in other vegetables and fruits and sample pretreatment.