Sensitive extraction of seven pesticide residues from environmental water with magnetic graphene oxide-based covalent organic framework.

The use of pesticides has increased with the development of agriculture. However, due to the trace content and the matrix's inherent complexity in environmental water, development of rapid and sensitive detection method present significant challenges in the analysis of pesticide residues. The study synthesized magnetic graphene oxide (MGO) by combining superparamagnetic nanoparticles with the easy modification of graphene oxide (GO). Covalent organic frameworks (COFs) were then modified to have a large specific surface area. Finally, magnetic graphene oxide-based covalent organic frameworks, namely MGO-COFs, were obtained with a spherical structure and used as magnetic solid-phase extraction materials, which was successfully used to determine the seven pesticide residues in environmental samples in conjunction with high performance liquid chromatography. The method has a wide linear range for the tested pesticides, with satisfactory correlation coefficients (R ≥ 0.099) and low detection limits (0.3-1.21 μg L). The correlation coefficients for all seven pesticides were high (R ≥ 0.9996). The spiked recoveries, exhibiting a range of 91.3 to 109 %, demonstrated that the developed MGO-COF-MSPE-HPLC-UV method is simple, efficient, and suitable for the analysis and detection of seven pesticide residues in environmental water.