Abstract:

A new boronate affinity monolithic material was prepared and used as the extraction medium of stir cake sorptive extraction (SCSE). The porous boronate affinity sorbent was prepared by in situ copolymerization of 3-acrylamidophenylboronic acid (APB) and divinyl benzene (DVB). To achieve optimum extraction performance for benzoylurea pesticides, several parameters, including desorption solvent, pH value, ionic strength in sample matrix, extraction and desorption times, were investigated in detail. At the same time, a simple, sensitive and environment friendly method for the determination of benzoylurea pesticides in water and juice samples was developed by the combination of SCSE-APBDVB with HPLC equipped with a diode array detector. Under the optimized experimental conditions, the limits of detection (S/N=3) for target analytes were 0.055-0.11 μg/L in water and 0.095-0.31 μg/L in juice. The precision of the proposed method was evaluated in terms of intra- and inter-assay repeatability calculated as RSD, and it was found that the RSDs were all below 9.0%. The developed method was successfully applied to the determination of benzoylurea pesticide residues in water and juice samples and satisfactory recoveries of spiked target compounds were in the range of 75.6%-109%. The results well demonstrate that the new sorbent can extract benzoylurea pesticides effectively through multi-interactions including boron-nitrogen coordination, hydrogen-bond and hydrophobic interactions between sorbent and analytes.

Key words: benzoylurea pesticides, boronate affinity sorbent, enrichment, high performance liquid chromatography (HPLC), monolithic material, stir cake sorptive extraction