Determination of azole fungicide residues in fruits and vegetables by magnetic solid phase extraction based on magnetic MOF sorbent in combination with high performance liquid chromatography

Abstract

A sample pre-treatment technology, based on magnetic MOF composite Fe3O4@DUT-5 as the adsorbent, combined with high performance liquid chromatography (HPLC) has been developed and used for the trace analysis of azole fungicide residues in fruits and vegetables. Characterization analysis shows that Fe3O4@DUT-5 has good stability and excellent saturation magnetism. Under the optimal conditions, the satisfactory enrichment factors (69.6–96.4), and good linearity (10–1000 μg L-1) could be achieved, as well as the low limits of detection (0.054 to 0.313 μg L-1) were proved to be below the maximum residue limits (MRLs) of azole fungicides in agricultural products (10.0 μg kg−1). Additionally, the proposed method has been successfully applied to the determination of target analytes in six fruits and vegetables. The achieved recovery (62.3–100.8%) and reproducibility (lower than 6.4%) meet the requirements of pesticide residue analysis. Moreover, the high adsorption capacity and stability remain unchanged after 5 cycles. And it has a strong saturation magnetization value, which provides a strong guarantee for recycling. As a novel adsorbent, Fe3O4@DUT-5 showed great potential in the extraction of pesticide residues in fruits and vegetables.