DETERMINATION OF HEXAVALENT CHROMIUM IN

An aqueous sample is filtered through a 0.45 µm filter and the filtrate is adjusted to a pH of 9 to 9.5 with a buffer solution. A measured volume of the sample (50-250 µL) is introduced into the ion chromatograph. A guard column removes organics from the sample before the Cr(VI) as CrO is separated on an anion exchange separator column. Post-column derivatization of the 4 2- Cr(VI) with diphenylcarbazide is followed by detection of the colored complex at 530 nm.