Eco-friendly dispersive liquid–liquid microextraction procedure based on solidification of floated organic drop coupled with back-extraction for preconcentration of rare earth elements.

In this study, a simple and efficient eco-friendly procedure for preconcentration of trace amounts of Y, Sm, Eu, Gd, Er and Yb was developed prior to determination by inductively coupled plasma optical emission spectrometry (ICP-OES). The extraction process involved two sequential steps. The first is based on ultrasonic-assisted emulsification solidified floating organic drop microextraction using morin and 1-undecanol as complexing and extraction agents, respectively. The analyte in the solidified floated organic drop was then back-extracted into aqueous solution of HNO3 to prevent the relapsing effect of the organic matrix on the performance of ICP-OES. The effect of various experimental parameters on the extraction efficiency was studied and optimised. The limits of detection were in the range of 0.053 (Y) – 0.086 (Sm) µg L−1 with linear dynamic analytical range of 0.3–1000 µg L−1 at the optimal conditions. The relative standard deviations (C = 20 µg L−1, n = 10) ranged from 1.7% (Eu) to 2.5% (Yb). Finally, the approach represented high efficiency in determining the rare earth elements in certified reference material and phosphite rock samples. [ABSTRACT FROM AUTHOR]