This study investigates application of multi-walled carbon nanotubes coated cellulose acetate membrane for on-line extraction and preconcentration of some rare earth elements (Y, La, Ce, Nd, Sm, Gd and Dy) prior to their determination by inductively coupled plasma optical emission spectrometry. Sample solutions containing rare earth elements (pH: 6.0) and l-(2-pyridylazo) 2-naphtol (4.0 × 10-5 mol L-1) were passed through the membrane (flow rate: 5.0 mL min-1). The adsorbed cations were subsequently eluted from the membrane and transferred into the plasma with nitric acid solution (flow rate: 3.0 mL min-1) for simultaneous determination of them. The effect of different experimental parameters on the performance of the method were studied and discussed. Under the optimized conditions and preconcentration of 25 mL of sample, the enrichment factors of 185-201 and the detection limits of 0.05-0.3 µg L-1 were obtained.
Keywords:
rare earth elements; preconcentration; on-line solid phase extraction; cellulose acetate membrane; multi-walled carbon nanotube; ICP OES
