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 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.

A magnetic chitosan/TiO2 composite material (MCT) was developed. MCT was successfully synthesized by a one-pot method using chitosan, TiO2, and Fe3O4.

In this work, an n-octadecylamine functionalized mesoporous carbon nanocomposite (ODA-MPC) was synthesized, and its novel application was demonstrated by utilizing it as a sorbent in matrix solid-phase dispersion (MSPD) of nine pesticide residues identified by gas chromatography-mass spectrometer. Here, the protection of the sorbent by the mesoporous fiber membrane enabled it to process complex aqueous matrices and made it advantageous to be used in MSPD. The results confirmed the excellent ability of ODA-MPC to remove matrix interferences and reduce matrix effects compared to the traditional solid phase extraction. In particular, the recoveries were 85.0–95.8% (n = 3) with relative standard deviations less than 5%. Additionally, nine pesticide residues in vegetables and fruit were satisfactorily extracted and detected.

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