FIA determination of CrIII in tap water with chemiluminescence detection

Cr-III has been determined by measuring the light emitted as a result of the Cr-III-catalysed reaction between luminol and hydrogen peroxide. Increase in the sensitivity of the determination was achieved by introducing bromide into the reaction mixture while the selectivity was improved by the addition of EDTA. All the operations were performed online in an automated FIA system. 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 varied between 10 and 20 mu g l(-1) with a typical coefficient of variation of 2% (n = 5).