Chromium is a silvery metal that naturally occurs in the Earth’s crust. Its name comes from the Greek word chroma, meaning color, which perfectly reflects the nature of this element. Chromium forms many compounds of different colors depending on the oxidation state. Thanks to this diversity, it has been used for years in many branches of industry. It is applied, among others, in the production of stainless steel, electroplating, glass manufacturing, cosmetics, dietetics, and as a pigment.
However, not all chromium compounds are safe. Particularly dangerous is hexavalent chromium (Cr VI), whose toxic effects have led to it being subject to legal regulation.
Why is chromium (VI) harmful?
Chromium in the oxidation state VI is a carcinogenic and mutagenic substance. It enters the body not only through the digestive system but also through the skin and respiratory tract. Symptoms of poisoning include vomiting, diarrhea, mucous membrane irritation, disturbances in the circulatory and respiratory systems, as well as skin problems and allergies. Long-term exposure significantly increases the risk of developing lung cancer. The toxic effects of chromium threaten not only humans but also animals.
Why was chromium (VI) included in the RoHS Directive?
The widespread use of chromium in everyday products made it necessary to limit its most dangerous form. That is why the RoHS Directive was introduced, prohibiting levels of certain hazardous substances in electrical and electronic equipment from exceeding set limits.
In the case of hexavalent chromium, the content in the finished product must not exceed 1000 ppm. This substance can be found in virtually any metal component of a device, such as screws, plates, or heating elements. Most often, it serves as an anti-corrosion additive, a pigment, or a component used in the chromating process of metals such as zinc, cadmium, or copper.
How is the presence of chromium (VI) detected?
Testing for chromium in samples is carried out in accordance with the RoHS Directive requirements. The most commonly used is a screening method with an XRF spectrometer. This is a fast technique that allows determination of the total chromium content in a sample. Its drawback, however, is the inability to distinguish between safe forms, such as Cr (III), and the hazardous Cr (VI).
Therefore, if XRF analysis indicates levels above permissible limits, a confirmatory method must be used. For this purpose, UV-Vis spectrophotometry is applied. Cr (VI) ions, when treated with appropriate reagents, form a colored complex whose absorbance can be measured to precisely determine the concentration in the sample.
Chromium testing at RCC
At the RCC Research and Development Center, we perform both types of testing. Our specialists not only analyze samples but also advise when additional testing methods should be used.
Thanks to many years of experience, we support manufacturers and distributors at every stage of the testing process. We help ensure that products comply with the RoHS Directive, thereby safeguarding user safety and compliance with EU law.