Preconcentration and atomic spectrometric determination of rare earth elements (Rees) in environmental samples

Abstract

Determination of rare earth elements (REEs) in environmental samples is usually performed by the plasma techniques, inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). Due to low concentrations of REEs and usually the presence of heavy matrix, an efficient separation and preconcentration technique is required prior to instrumental measurements in order to achieve accurate and reliable results. In this study, different types of zeolites (Clinoptilolite, Mordenite, Zeolite Y, Zeolite Beta), ion exchangers (Amberlite CG-120, Amberlite IR-120, Rexyn 101, Dowex 50W X18) and chelating resins (Muromac, Chelex 100, Amberlite IRC-718) were proposed as adsorbent materials for the preconcentration of REEs in environmental waters prior to their determination by ICP-OES. It was shown that REEs can be retained by these adsorbents quantitatively in a broad pH range (pH>4) and their desorptions from the adsorbents can be realized with acidic eluents. Of the sorbents investigated, clinoptilolite was chosen for the subsequent studies. Spike recovery tests were performed at various concentration levels in different water types including pure water, bottled drinking water, river water, sea water, and tap water, and were found to change between 85-90%.