BS EN 62321-7-2:2017 describes procedures to measure hexavalent chromium, Cr(VI), quantitatively in samples of polymers and electronics. This method employs organic solvent to dissolve or swell the sample matrix, followed by an alkaline digestion procedure to extract Cr(VI) from samples. Studies have shown that organic/alkaline solution is more effective than acidic solution in extracting Cr(VI) from soluble and insoluble samples. Minimal reduction of Cr(VI) to Cr(III) or oxidation of Cr(III) to Cr(VI) occurs under alkaline conditions.

For soluble polymers consisting of ABS (Acrylonitrile- butadiene-styrene), PC (Polycarbonate) and PVC (poly(vinyl chloride)), the samples are first dissolved in an appropriate organic solvent and Cr(VI) is then extracted by an alkaline extraction solution.

For insoluble/unknown polymers, or electronic materials that do not contain antimony (Sb), the samples are digested in a toluene/alkaline solution at 150 ?C to 160 ?C. Then the organic phase in the extracts are separated and discarded; the inorganic phase is retained for Cr(VI) analysis.

The Cr(VI) concentration in the extract is determined by its reaction under acidic conditions with 1,5-diphenylcarbazide. Cr(VI) is reduced to Cr(III) in the reaction with diphenylcarbazide which is oxidized to diphenylcarbazone. The Cr(III) and diphenylcarbazone form a red-violetcoloured complex in the reaction. The complex solution is measured quantitatively by a colorimeter or a spectrophotometer at 540 nm.


Cross References:
IEC 62321-1:2013
ISO 3696:1987
EN ISO 3696
EN 62321-1 (IEC 62321-1:2013) AS
EN 62321-2
EN 62321:2009
EN ISO 648
ISO 648:2008
IEC 62321-5:2013
IEC 62321:2008
ASTM E1272 - 02(2012)


Replaces BS EN 62321:2009 which remains current.

All current amendments available at time of purchase are included with the purchase of this document.