GB/T 39560.702-2021: Determination of certain substances in electrical and electronic products - Part 7-2: Hexavalent chrome - Determination of hexavalent chrome [Cr(VI)] in polymers and electronics by the colormetric method

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Scope

This Part of GB/T 39560 specifies the method for quantitative detection of hexavalent
chromium [Cr (VI)] in polymer and electronic samples. The determination method in
this Part uses an organic solvent to dissolve or swell the sample matrix, and then uses
an alkaline digestion procedure to extract hexavalent chromium from the sample.
Studies have shown that for the extraction of hexavalent chromium from soluble and
insoluble samples, organic/alkaline solutions are more effective than acidic solutions.
Under the condition of alkaline solution, the reduction of hexavalent chromium to
trivalent chromium or the oxidation of trivalent chromium to hexavalent chromium is
the least.
For soluble polymer samples composed of ABS (acrylonitrile-butadiene-styrene), PC
(polycarbonate) and PVC (polyvinyl chloride), first dissolve the sample in an
appropriate organic solvent. The hexavalent chromium is then extracted with alkaline
extraction solution.
For insoluble or unknown polymers or electronic materials that do not contain antimony
(Sb), first put the sample into a toluene/alkaline solution at 150°C to 160°C for digestion.
The organic phase in the extract is then separated and discarded. Retain the inorganic
phase for hexavalent chromium analysis.
The hexavalent chromium concentration in the extract is determined by reacting the
extract with 1,5-diphenylcarbazide under acidic conditions. During the reaction with
diphenylcarbazide, hexavalent chromium is reduced to trivalent chromium.
Diphenylcarbazide is oxidized to diphenylcarbazide. The trivalent chromium and
diphenylcarbazone then react further to form a purple-red compound. Then use a
colorimeter or spectrophotometer to quantitatively determine the purple compound
solution at 540nm.

Basic Data

Standard ID	GB/T 39560.702-2021 (GB/T39560.702-2021)
Description (Translated English)	Determination of certain substances in electrical and electronic products - Part 7-2: Hexavalent chrome - Determination of hexavalent chrome [Cr(VI)] in polymers and electronics by the colormetric method
Sector / Industry	National Standard (Recommended)
Classification of Chinese Standard	L10
Word Count Estimation	14,161
Issuing agency(ies)	State Administration for Market Regulation, China National Standardization Administration