Modified Magnetic Nanoparticles as a Novel Sorbent for Dispersive Magnetic Solid-Phase Extraction of Triazine Herbicides in Aqueous Media

In this study, a polythiophene/chitosan polymer and electrospinning polymer nanofibers as modifier compounds were used, and magnetic nanocomposites as a novel adsorbent were proposed, for the preconcentration of some triazines, including atrazine, ametryn, and terbutryn, in aqueous samples before GC. The synthesized magnetic nanoparticles, magnetic polymer nanofibers, and polythiophene magnetic nanocomposite were characterized by scanning electron microscopy. The separation of the target analytes from the aqueous solution containing the triazines and different magnetic nanocomposites were simply achieved by applying an external magnetic field. The extraction efficiency of magnetic polyamide nanofibers was enhanced as compared with other modified magnetic nanoparticles. The main factors affecting the extraction efficiency, including desorption conditions, nanocomposite component ratio, electrospinning time, sorbent amount, extraction time, ionic strength, and sample pH, were optimized. The developed method proved to be convenient and offers sufficient sensitivity and good reproducibility. Under optimized conditions, the method's LOD (S/N = 3) and LOQ (S/N = 10) were 1-5 and 15 ng L-1, respectively; good linearity was obtained within the range of 15-2000 ng L-1 for triazines, with correlation coefficients >0.9997. The RSD at the concentration level of 100 ng L-1 was 9-14% (n = 3). Furthermore, the method was successfully applied to the determination of triazines in real samples, in which relative recoveries of 98-103% were obtained. Compared with other methods, the current method is characterized by its ease, fast separation, and low detection limits.