On-line preconcentration of nickel on activated carbon prior to its determination by vapor generation associated to inductively coupled plasma optical emission spectrometry

Abstract

An on-line nickel preconcentration system implemented with chemical vapor generation associated to inductively coupled plasma optical emission spectrometry (VG-ICP-OES) was studied. Trace amounts of nickel were preconcentrated by sorption on a minicolumn packed with activated carbon at pH 5.0. The analyte retained was removed from the minicolumn with 0.3 mol l⁻¹ hydrochloric acid. After that, volatile species of nickel were generated by merging the acidified sample and sodium tetrahydroborate(III) in a continuous flow system. The gaseous analyte was subsequently introduced via a stream of Ar carrier into the inlet tube of the inductively coupled plasma torch. For the preconcentration procedure, an enrichment factor of 36-fold for a sample volume of 25 ml was obtained. The detection limit (DL) obtained was 0.06 μg l⁻¹. The precision (RSD) for ten replicate determinations at a level of 0.5 μg l⁻¹ was 4.0%. Potential interfering effects on the Ni signal were examined.