No single measurement method can be used for all materials© EU, 2012
Review of measurement methods for nanoparticle sizing
A JRC report, published today, presents an in-depth review of methods available to measure the size of nanoparticles. Following the adoption of the definition of the term 'nanomaterial' in October 2011, it identifies relevant measurement methods and key challenges for measuring nanoparticle size in the regulatory context. The report underlines that no single measurement method can be used for all materials to determine if each of them falls within the regulatory definition. Different methods will be required depending on the material under investigation.
The report gives an overview of the capabilities of currently available measurement methods, including techniques such as electron microscopy, dynamic light scattering and centrifugal liquid sedimentation, among others. It also identifies measurement issues that remain to be solved.
The conclusions highlight the practical challenges of measuring materials with widely varying properties. None of the currently available methods can determine whether all kinds of potential nanomaterials meet the regulatory definition or not. Therefore, a proper combination of measurement methods is required. The reliability of each of the measurement methods used in such combined, tiered approaches will need to be thoroughly checked in dedicated method validation studies.