Diglycolamide-grafted Fe3O4/polydopamine nanomaterial as a novel magnetic adsorbent for preconcentration of rare earth elements in water samples prior to inductively coupled plasma optical emission spectrometry determination

In this work, magnetic nanomaterials were synthesized by grafting diglycolamide (DGA) derivatives onto polydopamine (PDA) functionalized magnetic nanomaterials (Fe 3 O 4 @PDA@DGA). The adsorption behaviors of Fe 3 O 4 @PDA@DGA for rare earth elements (REEs) were evaluated. The characterization results indicated that the Fe 3 O 4 nanoparticles form a hexagonal-like two-dimensional projection shape, and DGA is successfully grafted onto the surface of the nanomaterials. By using Fe 3 O 4 @PDA@DGA nanomaterials as the adsorption material, a novel method for magnetic solid phase extraction (MSPE) coupled with inductively coupled plasma optical emission spectrometry (ICP-OES) was developed, which can quantitatively determine trace REEs in environmental water. With the MSPE procedure, the parameters affecting the adsorption behaviors of the REEs on Fe 3 O 4 @PDA@DGA nanomaterials, such as pH, ultrasonic adsorption time, mass and solution volume were investigated systematically. Under the optimum experimental conditions, the limits of detections (LODs) and the relative standard deviations (RSDs) of 16 REEs (C = 10 µg L −1 , n = 7) were in the range of 0.039 µg L −1 for Eu to 0.425 µg L −1 for Nd and 1% for La to 3.9% for Gd. The linear range of the calibration curve over 2–1000 ng mL −1 (R 2  > 0.999) was obtained for the target analytes. This developed method was applied for the environmental samples and the recoveries were 95.8–105.8% for the spiked water. The proposed MSPE-ICP-OES method has the advantages of easy separation, simple operation, good anti-interference capability, fast adsorption and elution kinetics, low detection limits, high sensitivity and fast analysis speed, thereby acting as a potential application for the simultaneous analysis of trace REEs in environmental samples.