Photometric determination of the decolouration of the bismuth xylenol orange complex

The complexing agents are determined relative to the bismuth complexing index IBiC. The following conversion factors hold true:
1 mg/l IBiC = 1.4 mg/l EDTA (M = 292 g/mol) = 1.0 mg/l NTA
This method is a screening test which covers strong complexing agents. If the result is positive, metals present in the sample may be partially or completely withdrawn from the photometric determination. For the analysis of metals in this case a decomposition (e. g. with Crack set Cat. No. 918 08 or NanOx Metal Cat. No. 918 978) has to precede the photometricmeasurement.