Dispersive micro-solid-phase extraction of benzoylurea insecticides in water samples with hyperbranched polyester composite as sorbent

A pretreatment method using hyperbranched polyester (HBPE) composite as sorbent based on dispersive micro-solid-phase (d-μ-SPE) extraction preceding high-performance liquid chromatography analysis was developed for the determination of benzoylurea insecticides (BUs) in water samples. Parameters that may influence the extraction efficiency, such as the diameter and the amount of the sorbent, extraction and desorption time and the pH value of the solution, were investigated and optimized using batch and column procedures. Under optimized conditions, good linearity was obtained for all of the tested compounds, with r values of at least 0.9924. The linearity of the method was determined in the range of 1-25 000 μg L⁻¹. The limits of detection (LODs) ranged from 0.024 to 0.068 μg L⁻¹. The recoveries of the four benzoylurea insecticides in water samples increased from 85.50-96.12%. The results confirmed the possibility of using hyperbranched polyester in the determination of relatively hydrophobic trace pesticides residues. Finally, the proposed method was applied to the determination of BUs in water samples with satisfactory results.