A novel vortex-assisted dispersive liquid-phase microextraction procedure for preconcentration of europium, gadolinium, lanthanum, neodymium, and ytterbium from water combined with ICP techniques

A novel, simple, and rapid extraction method based on vortex-assisted dispersive liquid-phase microextraction (VA-DLPME) for the preconcentration of La, Eu, Nd, Gd and Yb in water samples combined with inductively coupled plasma optical emission spectrometry (ICP OES) and inductively coupled plasma mass spectrometry (ICP-MS) detection is described. Butan-1-ol and 1-(2-pyridilazo)2-naphthol (PAN) were used as the extractant solvent and complexing agent, respectively. The main experimental parameters affecting the complexation and extraction of the analytes, including pH, PAN concentration, salt addition, and extractant solvent volume, were optimized. Under optimum microextraction conditions, detection limits obtained by ICP OES and ICP-MS detection were 0.3-1.1 g L-1 and 3.0-4.0 ng L-1, respectively. The developed method was applied to water samples and a certified reference material (CRM) from the National Research Council (Coastal seawater - CASS-4). Recovery values of the rare earth elements for spiked water samples (tap water, groundwater and seawater) were 90-104% for ICP OES and 83-92% for ICP-MS. The proposed VA-DLPME procedure permits the addition of the complexing agent and extractant solvent simultaneously into the sample, avoiding the use of a centrifugation step and the use of potentially toxic solvents such as methanol and chloroform.