诚求：ROHS测试中检测六价铬含量的整套方法

10 Determination of Hexavalent Chromium (Cr VI) by Colorimetric Method
10.1 Scope, Application and Summary of Method
This method describes the procedures to measure hexavalent chromium, i.e. Cr(VI),
quantitatively in samples of polymer materials, and electronic components. Hexavalent
chromium is toxic to human beings and classified as mutagenic and carcinogenic. All potential
Cr(VI) containing samples and reagents used in the method shall be handled with appropriate
precautions.
This method uses alkaline digestion procedures to extract hexavalent chromium from
samples. Studies have shown that alkaline solution is more effective than acidic solution in
extracting Cr(VI) from water soluble and insoluble samples. Minimal reduction of native Cr(VI)
to Cr(III) or oxidation of native Cr(III) to Cr(VI) occur in the alkaline extraction solution.

The Cr(VI) concentration in the extract is determined by its reaction in acid condition 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 further form a red-violet
colored complex in the reaction.
The complex solution is measured quantitatively by a colorimeter or a spectrophotometer at
540nm.
If high levels of contaminations such as organics are present in the samples, an ion
chromatographic method is recommended after alkaline digestion, i.e. a measured amount of
alkaline extract is filtered and injected into the ion chromatograph. Post-column derivatization
of the Cr(VI) with diphenylcarbazide is followed by detection of the colored complex at 540nm.
Other alternative digestion methods or analytical techniques may be utilized once the
performance effectiveness has been validated according to the performance based
measurement system criteria (reference to section 10.6.5 Quality Control).
Possible interference may be caused by reduction of hexavalent chromium, oxidation of
trivalent chromium, or color interference in the colorimetric measurement. The interference
parameters may include but not limited to pH, ferrous iron, sulfide, hexavalent molybdenum,
mercury salts, etc.

请注意：该法有干扰,三价Cr可能被氧化为六价；或六价还原为3价。pH值，颜色干扰，亚铁，硫化物，汞盐等均有影响。

问题：怎样保证测到的6价Cr就是原始样品中的含量？怎样证明无转变？

办法：用原子吸收测总量，保证总Cr低于6价Cr控制限即可！

谢谢你了，
不过这个英文文献我已经看过了，有没有其他的啊？

你好厲害,除了Cr檢測方法,有沒有其它五個成分的檢測方法.拜托.


可否email給我:fuqin@harbourring.com.hk (因為沒有時間上网).

你可以去专题讨论区->RoHS->RoHS检测样品前处理方法 polypalm
中一个有关前处理的帖子下载到所有的。

陸價鉻同附件，僅供參考