Magnetic solid-phase extraction using poly(para-phenylenediamine) modified with magnetic nanoparticles as adsorbent for analysis of monocyclic aromatic amines in water and urine samples

In the present work, a simple and effective method based on magnetic separation has been developed for the extraction of monocyclic aromatic amines in water and urine samples using poly(para-phenylenediamine) modified with Fe3O4 nanoparticles (PpPD/Fe3O4) as an adsorbent. The chemical structures of the sorbent were characterized by field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectrophotometer (FT-IR). Various parameters affecting on the extraction efficiency of desired analytes, such as pH of solution, desorption conditions, extraction time, salt effect and amount of adsorbent have been investigated and optimized. The obtained optimal conditions were: sample pH, 6; amount of sorbent, 20 mg; sorption time, 2 min; elution solvent and its volume, dichloromethane and chloroform (3:1 v/v), 250 μL; elution time, 30 s and without addition of NaCl. Under the optimum conditions, detection limits in the range of 0.007-0.01 ng mL-1 were obtained by gas chromatography-flame ionization detector (GC-FID). The calibration curves were linear in the range 0.05-100 ng mL-1 with a correlation coefficient better than 0.9953. In addition, a satisfactory reproducibility was achieved by evaluating the intra- and inter-day precisions with relative standard deviations (RSDs) less than 5.9 and 7.3%, respectively. The proposed procedure has been successfully applied to the determination of target analytes in water and urine samples. The results demonstrated that the developed method is simple, inexpensive, accurate and remarkably free from interference effects.