Determination of phthalate esters at trace level from environmental water samples by magnetic solid-phase extraction with Fe@SiO2@polyethyleneimine magnetic nanoparticles as adsorbent prior to high-performance liquid chromatography.

In this work, polyethyleneimine grafted silica-coated nanoscale zero valent iron (Fe@SiO2@PEI) has been successfully synthesized and was investigated to be an effective adsorbent for efficient enrichment of five phthalate esters such as diphenyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, diphenyl isophthalate, and dicyclohexyl phthalate (DPP, DBP, BBP, DPIP, and DCHP) from environmental water samples. The structure and morphology of the materials were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction(XRD). The parameters that influenced the enrichment performance such as amount of sorbent, sample pH, type of eluent, volume of eluent, salting-out effect, adsorption time, and desorption time were investigated. Under optimal conditions, excellent linear relationships were found in the concentration range from 0.5 to 100 μg L(-1), the limits of detection (S/N = 3) were in the range of 0.26-0.45 μg L(-1), and the intra-day and inter-day precisions (n = 6) were in the range of 3.7-4.8 and 3.2-4.3 %, respectively. The developed method was evaluated with real water samples, and satisfied spiked recoveries in the range of 99-104 % were achieved. The experimental results proved that Fe@SiO2@PEI had good adsorption for phthalate esters, and would be a good adsorbent for the magnetic solid-phase extraction of important pollutants from environmental water samples.ᅟ Graphical abstract A flowchart of the synthesis of polyethyleneimine grafted silica coated nanoscale zero valent iron (Fe@SiO2@PEI) and the process of the developed magnetic solid phase extraction of phthalate esters before the analysis by high performance liquid chromatography.