Jovian LabsThe EU definition of nanomaterial, and how to screen a powder with electron microscopy
A practical reading of Commission Recommendation 2022/C 229/01 of 10 June 2022, for R&D and product stewardship teams. Not legal advice: sector regulations (cosmetics, food, biocides, REACH) have their own texts and guidance.
What the definition says
A nanomaterial is a natural, incidental or manufactured material consisting of solid particles, on their own or as identifiable constituent particles in aggregates or agglomerates, where 50% or more of the particles in the number-based size distribution meet at least one condition:
- (a) one or more external dimensions between 1 nm and 100 nm;
- (b) an elongated shape (rod, fibre, tube) with two external dimensions below 1 nm and the other above 100 nm;
- (c) a plate-like shape with one external dimension below 1 nm and the others above 100 nm.
Particles with at least two orthogonal external dimensions above 100 µm need not be considered, and a material with a volume specific surface area below 6 m²/cm³ is not a nanomaterial.
Why electron microscopy
The criterion counts particles by number and looks at their smallest dimension, including particles inside agglomerates. Electron microscopy sees individual particles and their shape, which is why it is a reference method. On an image, the smallest external dimension is approximated by the minimum Feret diameter, the smallest width of the particle's projection.
Reading a screening result
- Count enough particles. The EU NanoDefine project recommends at least 500 for electron microscopy.
- Look at the interval, not just the percentage. A result of 55% with an interval from 44% to 66% does not settle the question; a result of 95% with an interval from 91% to 98% does.
- Know what pushes the number down. Particles below the detection limit, particles hidden in agglomerates and platelets lying flat (their thickness is not seen) all make a material look less “nano” than it is.
The particle size tool reports the share of particles at or below 100 nm, its uncertainty and a meets / not met / borderline verdict, with a PDF report. 1 USD per image, free demo.
Version française : la définition européenne des nanomatériaux.