On-Line Solid Phase Extraction and Simultaneous Determination of Hafnium and Zirconium by ICP–Atomic Emission Spectroscopy

Abstract

A new simple flow injection analysis (FIA) system is described for on-line preconcentration by solid phase extraction and simultaneous determination of Hf and Zr in different samples using inductively coupled plasma atomic emission spectroscopy with a charge coupling detector (CCD). Quinalizarin (QA) was loaded on an octadecyl silica-polyethylene mini-column for the retention of Hf and Zr ions in complexed form. A 0.3 M ammonium acetate was used as buffer for providing suitable conditions for complexation and increasing reproducibility. Retained ions on the solid phase were then eluted by a solution containing 3.0 M HCl and 0.5 M HNO3. In this work, for reducing bandwidths of eluted ions, elution of minicolumn was carried out from opposite direction. The same solution was used as both carrier and eluent, in order to increase the reproducibility. The eluted ions were introduced into the conventional nebulizer of ICP–AES instrument. Effects of different parameters, including instrumental parameters of ICP and FIA were optimized. An enrichment factor of 330 for each analyte ion was obtained at a concentration level of 80 ppb. The detection limits of the proposed method for Hf and Zr were 0.16 ng mL−1 and 0.04 ng mL−1 respectively. The ability of the method for the recovery of Hf and Zr ions was tested in the presence of several diverse metal ions in a synthetic mixture and some real matrices. It was also applied to the determination of Zr and Hf ions in a standard soil and in a standard alloy as real samples.