Magnetic dispersive solid-phase microextraction of fourteen rare earth elements (REEs) from herbs, tea, and water using bimetallic spinel magnetic NiZnFe2O4 nanomaterial followed by ICP-OES determination.

In this work, bimetallic spinel magnetic NiZnFe2O4 (BS-M-NZF) nanomaterial was prepared using a sol-gel route. By using BS-M-NZF as an adsorbent, a magnetic dispersive solid phase microextraction (M-D-SPμE) method coupled with ICP-OES was developed to determine 14 REEs in tea, herbs and waters. Parameters affecting M-D-SPμE of 14 REEs have been investigated. They were at pH 6.0; contact times were 1 min and 30 s; volume was 40 mL; adsorbent amount was 100 mg; and the eluent was 1 mol L-1 HNO3 (4 mL). The LODs and the RSDs% of 14 REEs changed from 0.014 μg L-1 (Yb) to 0.362 μg L-1 (Sm) and 0.96% (Yb) to 2.81% (Lu), respectively. The accuracy of the M-D-SPμE was validated by analyzing a SPS-SW2 Batch 145 (except for Sm). Besides, it was verified by recovery studies in the LGC6016 Estuarine Water, NW-TMDA-54.6 Lake water, tea, herbs, and water, which changed from 89 to 114%. The developed M-D-SPμE-ICP-OES method offers advantages such as fast adsorption/elution kinetics, high sensitivity, low LODs, rapid analysis, selectivity, accuracy, and simplicity.