Fast preconcentration of trace rare earth elements from environmental samples by di(2-ethylhexyl)phosphoric acid grafted magnetic nanoparticles followed by inductively coupled plasma mass spectrometry detection

In this work, di(2-ethylhexyl)phosphoric acid (P204) grafted magnetic nanoparticles were synthesized by fabricating P204 onto Fe3O4@TiO2 nanoparticles based on Lewis acid-base interaction between Ti and phosphate group under weakly acidic condition. The prepared Fe3O4@TiO2@P204 nanoparticles exhibited excellent selectivity for rare earth elements, and good anti-interference ability. Based on it, a method of magnetic solid phase extraction (MSPE) combined with inductively coupled plasma mass spectrometry (ICP-MS) was developed for fast preconcentration and determination of trace rare earth elements in environmental samples. Under the optimal conditions, the detection limits of rare earth elements were in the range of 0.01 (Tm)–0.12 (Nd)ngL−1 with an enrichment factor of 100-fold, and the relative standard deviations ranged from 4.9 (Pr) to 10.7% (Er). The proposed method was successfully applied to the determination of rare earth elements in environmental samples, including river water, lake water, seawater and sediment. Graphical abstract [Display omitted] •P204 was grafted to Fe3O4@TiO2 NPs by Lewis acid-basic interaction between Ti and phosphate group.•Fe3O4@TiO2@P204 NPs show good selectivity for REEs and good anti-interference ability.•A method of MSPE-ICP-MS was developed for fast analysis of trace REEs in environmental samples.