On-line preconcentration by a Schiff's base adsorbed on surfactant coated activated carbon and determination of nickel in natural water samples by flow injection-inductively coupled plasma optical emission spectrometry (FI-ICP-OES)

摘要

An on-line nickel preconcentration and determination system implemented with inductively coupled plasma optical emission spectrometry (ICP-OES) associated to flow injection (FI) was studied. Trace amounts of nickel were preconcentrated by sorption on a conical minicolumn packed with activated carbon (AC) modified with a Schiff's base 1,2-bis(salicylidene amino)ethane(SALET) at pH 5.0. The nickel was removed from the minicolumn with 20% nitric acid. An enrichment factor of 80-fold for a sample volume of 50 ml was obtained. The detection limit (DL) value for the preconcentration method proposed was 78 ng l~(-1).The precision for ten replicate determinations at the 0.5 mu g l~(-1) Ni level was 2.5% relative standard deviation (R.S.D.), calculated from the peak heights obtained. The calibration graph preconcentration method for nickel was linear with a correlation coefficient of 0,9998 at levels near the detection limits (DL) up to at least 110 mu g l~(-1). The method was successfully applied to the determination of nickel in natural water samples.