FIA determination of Cr-III in tap water with chemiluminescence detection

Cr-III has been determined by measuring the light emitted as a result of th e Cr-III-catalysed reaction between luminol and hydrogen peroxide. Increase in the sensitivity of the determination was achieved by introducing bromid e into the reaction mixture while the selectivity was improved by the addit ion of EDTA. All the operations were performed online in an automated FIA s ystem. The calibration curve for Cr-III was linear in the range 0-500 mu g l(-1) and the limit of detection was 0.5 mu g l(-1). The method was applied to the determination of Cr-III in tap water; the Cr-III concentration vari ed between 10 and 20 mu g l(-1) with a typical coefficient of variation of 2% (n = 5).