Determination of rare earth elements in environmental materials by ICP-MS after liquid-liquid extraction

Inductively coupled plasma-mass spectrometry (ICP-Ms) has been employed to study the concentrations of rare earth elements (REEs) in environmental samples available from the National Institute of Standards and Technology (NIST), the Bureau of European Communities (BCR), and the German Environmental Specimen Bank (ESB). The REEs were separated from the matrix and simultaneously pre-concentrated using liquid-liquid extraction with bi(2-ethylhexyl)-ortho-phosphoric acid (HDEHP) in toluene as a selective reagent at pH=2. Subsequent back extraction of the elements into the aqueous phase was accomplished with 6M HNO3. the results agree well with the data available on many of these materials and supplement the information reported on the concentration of the various REFs in these materials.