Spectrophotometric determination of copper(II) at low mu g 1(-1) levels using cation-exchange microcolumn in flow-injection

A simple spectrophotometric flow-injection method is reported for the highl y sensitive and fast determination of copper(II). The method is based on th e formation of coloured Cu(II)-(4-methylpiperidinedithiocarbamate)(2) compl ex when the copper solutions are introduced into a tertiary reagent stream containing 4-methylpiperidinedithiocarbamate. The coloured complex is then selectively monitored at 435 nm. To increase interactions between copper(II ) and colour forming reagent and preconcentrate of copper(II), a microcolum n containing strong cation exchange resins was placed between injection man ifold and spectrophotometer. The system required no mixing chamber and allo wed a sample throughput > 60 sample h(-1). The calibration graph was linear in the range 5-100 mu g 1(-1). The detection limit was < 0.5 mu g 1(-1) fo r 20 mu 1 injection volume of copper(II) ion solution. The developed method was applied to environmental, copper processing water, and ore samples. (C ) 1999 Elsevier Science B.V. All rights reserved.