Magnetic polydopamine modified with deep eutectic solvent for the magnetic solid-phase extraction of sulfonylurea...

A novel magnetic solid-phase extraction (MSPE) technique coupled with ultra performance liquid chromatography (UPLC) has been developed for the determination of four sulfonylurea herbicides (sulfosulfuron, bensulfuron-methyl, pyrazosulfuron-ethyl and halosulfuron-methyl) in aqueous samples. The key point of this method was the application of a novel magnetic nanomaterial (Fe₃O₄ @ PDA-DES). The functional groups, morphology, and magnetic properties of this magnetic nanomaterial were investigated through fourier transformed infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and X-ray diffraction (XRD) respectively. The main factors which could affect the experiment results were optimized. Under the optimum conditions, the linearity of this method ranged from 5.0-200 μg L^-1 for all analytes, with correlation coefficients (r) ≥0.9901. The enrichment factors were between 495 and 630, and the relative standard deviations (RSDs) were less than 3.6%. The limits of detections (LODs) varied from 0.0098 to 0.0110 μg L^-1. In the final experiment, the developed method has been successfully applied to the determination of sulfonylurea herbicides in environment and drinking water samples, and the obtained recoveries were between 61.3% and 108.6%.