Traços de metais pesados em brinquedos
A major part of the toys which are available in the American and European market are “made in China”. Just recently, there have been several occasions where potentially hazardous materials had been used in Chinese toys which lead to expensive product recalls. Since the EU directive RoHS (Restriction of hazardous substances) has come into force, there are strict limits for the amount of heavy metals, such as lead, cadmium and mercury, allowed in consumer goods.
A major part of the toys which are available in the American and European market are “made in China”. Just recently, there have been several occasions where potentially hazardous materials had been used in Chinese toys which lead to expensive product recalls. Since the EU directive RoHS (Restriction of hazardous substances) has come into force, there are strict limits for the amount of heavy metals, such as lead, cadmium and mercury, allowed in consumer goods.
In order to prove traces of heavy metals in toys reliably, it is absolutely necessary to carry out sample preparation with heavy-metal-free tools. First of all, the toy has to be dismantled and the assemblies have to be separated into different analysis groups (e.g. plastics of different colours, electronic parts etc.). In a next step these are ground to a size of 3 – 4 mm. The Heavy-Duty Cutting Mill SM 2000 with its offset hard-metal cutters and powerful drive is ideally suited for the preliminary size reduction of such heterogeneous sample materials. The sample is now divided into representative sub-samples with the help of a rotary tube divider. The sub-samples are further homogenized in the Ultra Centrifugal Mill ZM 200. It achieves a final fineness below 200 µm in a very short time and is gentle on the material. It is recommendable to use liquid nitrogen or dry ice as a grinding aid. Cooling not only improves the breaking properties of the material but also helps to preserve volatile substances which might otherwise be affected by the frictional heat. Heavy-metal-free grinding tools are available for both mills so that the subsequent analysis is not influenced. <o:p></o:p>
In the document “Procedures for the Determination of Levels of Regulated Substances in Electrotechnical Products” issued by the International Electrotechnical Commission (IEC) the use of the RETSCH mills SM 2000 and ZM 200 is explicitly recommended for the neutral-to-analysis preparation of electric/electronic goods.<o:p></o:p>