Preparation of a ZIF-67-modified magnetic solid phase extraction material and its application in the detection of pyridine ring insecticides

In order to achieve rapid and effective analysis of praziquantel and pymetrozine residues in food, a new magnetic solid phase extraction (m-SPE) material based on GO and ZIF-67 was synthesized. Because the release of ZIF and GO materials may lead to secondary environmental pollution and their separation from solutions is difficult, ZIF-67 loaded on sheet-like MGO@PDA, a magnetic porous nano-composite, was fabricated by a convenient method at room temperature. The poly-dopamine (PDA) layer can improve the hydrophilicity of the material. The resultant MGO@PDA@ZIF-67 preserved the properties of ZIF-67 and MGO. The adsorbent material was characterized by XRD, VSM, TEM, SEM, TGA, XPS and FTIR experiments. An m-SPE technique was developed to selectively enrich two pyridine ring insecticides (praziquantel and pymetrozine) using high performance liquid chromatography (HPLC). The adsorption mechanism was investigated. Results showed that the maximum adsorption capacities of the new material for praziquantel and pymetrozine are 22.68 and 24.27 mg g −1 , respectively. The method was successfully applied to the analysis of praziquantel and pymetrozine in vegetable samples with satisfactory recoveries (92.3%-102.8%) and precisions. Due to the advantages of easy preparation, high efficiency, and renewability, the prepared hydrophilic magnetic porous nano-composite is an excellent candidate for adsorption and separation and provides a promising magnetic ZIF-67 material for multi-component system separation. An advanced and reliable m-SPE material of a water-stable ZIF was developed for the determination of trace praziquantel and pymetrozine in spinach and broccoli.