Facile synthesis of new nano sorbent for magnetic solid-phase extraction by self assembling of bis-(2,4,4-trimethylpentyl)-dithiophosphinic acid on Fe3O4@Ag core@shell nanoparticles: Characterization and application

A novel sorbent for magnetic solid-phase extraction by self-assembling of organosulfur compound. (bis-(2,4.4-trimethylpentyl)-dithiophosphinic acid), onto the silver-coated Fe3O4 nanoparticles was introduced. Due to the formation of covalent bond of S-Ag, the new coating on the silver surface was very stable and showed high thermal stability (up to 320 C). The size, morphology, composition, and properties of the prepared nanoparticles have also been characterized and determined using scanning electron microscopy (SEM), energy-dispersive X-ray analyzer (EDX), dynamic light scattering (DLS), Fourier transform-infrared (FT-IR) spectroscopy, and thermal gravimetric analysis (TGA). Extraction efficiency of the new sorbent was investigated by extraction of five polycyclic aromatic hydrocarbons (PAHs) as model compounds. The optimum extraction conditions for PAHs were obtained as of extraction time, 20 min: 50 mg sorbent from 100 mL of the sample solution, and elution with 100 mu L of 1-propanol under fierce vortex for 2 min. Under the optimal conditions, the calibration curves were obtained in the range of 0.05-100 mu g L-I (R-2 > 0.9980) and the LODs (S/N = 3) were obtained in the range of 0.02-0.10 mu g L-1. Relative standard deviations (RSDs) for intra- and inter-day precision were 2.6-4.2% and 3.6-8.3%, respectively. In addition, feasibility of the method was demonstrated with extraction and determination of PAHs from some real samples containing tap water, hookah water as well as soil samples with relative recovery of 82.4-109.0% and RSDs of 3.5-11.6%. (C) 2012 Elsevier B.V. All rights reserved.