GB/T 39560.702-2021 Active National standards

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

Publish Date: 2021-10-11 Implement Date: 2022-05-01 For services related to genuine standard inquiry, procurement, translation, and other related services in China, please Contact Us

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Basic Information

Standard Code: GB/T 39560.702-2021

Standard Type: National standards

Standard Status: Active

is_force_gb: no

CCS Name: Electronic components

ICS Name: Electronic components comprehensive

Publish Date: 2021-10-11

Implement Date: 2022-05-01

Pages: 14 pages

Scope

This part of GB/T 39560 specifies a method for quantitatively detecting hexavalent chromium [Cr(VI)] in polymer and electronic component samples. The determination method in this part uses organic solvents to dissolve or swell the sample matrix, followed by 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, the extraction effect of organic/alkaline solutions is more effective than that of acidic solutions. Under alkaline solution conditions, the reduction of hexavalent chromium to trivalent chromium or the oxidation of trivalent chromium to hexavalent chromium is minimal.
For soluble polymer samples composed of ABS (acrylonitrile-butadiene-styrene), PC (polycarbonate), and PVC (polyvinyl chloride), the samples are first dissolved with appropriate organic solvents, and then hexavalent chromium is extracted with an alkaline extractant solution.
For insoluble or unknown polymer or electronic component materials that do not contain antimony (Sb), the samples are first digested in toluene/alkaline solution at 150 ℃ to 160 ℃, and then the organic phase in the extract is separated and discarded, leaving the inorganic phase for hexavalent chromium analysis.
The concentration of hexavalent chromium in the extract is determined by reacting the extract with 1,5-diphenylcarbazide under acidic conditions. During the reaction with 1,5-diphenylcarbazide, hexavalent chromium is reduced to trivalent chromium, and 1,5-diphenylcarbazide is oxidized to 1,5-diphenylcarbazone. Then trivalent chromium and 1,5-diphenylcarbazone further react to form a purple-red compound. The solution of this purple-red compound is then quantitatively measured using a colorimeter or spectrophotometer at 540 nm.