Magnetic Dispersive Solid Phase Microextraction Followed by High Performance Liquid Chromatography for Determination of Benzoylurea Pesticides in Water and Juice samples

A magnetic extraction sorbent based on Fe3O4@ poly (methacrylic acid-co-ethylene dimethacrylate) (Fe3O4@ MAED) was synthesized using methacrylic acid and ethylene dimethacrylate as monomer and cross. linker, respectively. The magnetic sorbent was characterized by FTIR spectroscopy, elemental analysis and transmission electron microscopy. At the same time, the Fe3O4@ MAED was used to extract four benzoylurea pesticides in water and juice samples under magnetic dispersive solid phase microextraction (MDSPME) format. To obtain the optimal extraction conditions, several parameters, including the amount of sorbent, desorption solvent, extraction and desorption time, pH value, and ionic strength in sample matrix were investigated. Based on this, a fast, simple and sensitive method for the determination of benzoylurea pesticides in water and juice samples was developed by the combination of MDSPME with HPLC equipped with diode array detector. Under the optimized experimental conditions, the developed method possessed expected linear dynamic ranges, coefficients of correlation (R-2 > 0.99) and sensitivity. The limits of detection (S/N = 3) for target analytes were 0.10-0.19 mu g/L in water and 0.12-0.30 mu g/L in juice, respectively. The RSDs for intra-day were less than 7% and inter-day RSDs were less than 11%. The developed method was successfully applied to the determination of benzoylurea pesticides residues in water and juice samples and the recoveries of spiked target compounds were in the range of 69.4% - 118.0%. The results demonstrated that the Fe3O4@ MAED could extract benzoylurea pesticides effectively through multi-interactions including hydrophobic, hydrogen-bond and ion. exchange interactions between sorbent and analytes.