A Guide to Avoid Method Bias of Chromium (III,VI) Chemiluminescence Determination by Luminol-Hydrogen Peroxide Reaction - Application to Water Samples

Cr(III) and/or Cr(VI) determinations based on light emission produced by luminol oxidation by hydrogen peroxide in basic aqueous solution catalyzed by Cr(III) were studied in order to diagnose and/or avoid method bias. The calibration step was optimized, and the usefulness of the method for speciating chromium was tested. The use of the standard addition method in the linear interval concentration range made it possible to diagnose the accuracy of the method for real samples. Good results were obtained for several real water samples containing chromium at different concentrations. The proposed protocol made the method traceable with an appropriate certified reference material and with the reference method.