Determination of trace amounts of nickel by chelating ion exchange and on-line enrichment in flow injection spectrophotometry

Abstract

Trace amounts of nickel were determined after preconcentration at batch levels and by flow injection using chelating resins. Various experimental conditions were optimized for the preconcentration procedure. The batch procedure for preconcentration was highly dependent on pH. In the continuous-flow method, nickel was eluted from the resin with 20 µl of 2 mol l^–1 hydrochloric acid and was determined at 445 nm as the nickel–dimethylglyoxime complex. Column chromatographic separations of copper and nickel did not show any cross-contamination. The flow method was also used for the determination of nickel in various brands of chocolate and vegetable oil after preconcentration