RoHS/WEEE Element Hexavalent Chromium

Hexavalent Chromium Cr⁶⁺

Hexavalent Chromium (Cr⁶⁺) is a known carcinogen and hence is included in the RoHS 2002/95/EC Directive which limits the maximum level of Cr⁶⁺ at 1000 ppm.

Options for Testing and Measuring
XRF analyzers can be used for quick, non destructive testing to measure total elemental Cr.

• While XRF is only an elemental technique (that is, it can measure total Cr, but cannot speciate Cr⁶⁺), it still remains a very useful tool. For example, if total Cr measured is below the required RoHS threshold, it also means that Cr⁶⁺. is below that threshold.
• Since XRF is an elemental technique and not species specific, additional testing must be done to determine the specific levels of Cr⁶⁺ (if elemental Cr is detected)

For the determination of Cr⁶⁺, a more sensitive colorimetric technique is required, specifically Ultraviolet Visible Spectroscopy For this test method, sample preparation by alkaline digestion (EPA 3060A) or boiling water extraction (EPA 7196A) is required. Thermo Fisher Scientific’s GENESYS series spectrophotometers can be used to precisely measure hexavalent chrome levels in your sample.

Where is it used
Hexavalent Chromium (Cr⁶⁺) (also known as Cr VI) has been commonly used as a coating on a variety of materials, often to act as a corrosion inhibitor. Cr⁶⁺ can also be used in pigments, dyes, paints, inks, textiles, plastics and a host of other materials.