NanoValid D.5.47 Annex 1: Inter-laboratory comparison on measurand particle size of ~15 nm Lys-SNPs-B1 Silica Nanoparticles Particles

An inter-laboratory comparison on the particle size, expressed as mean diameter <em>d</em>, of nanoscaled SiO₂ (#14 BAM Silica, ~15 nm diameter (see D.5.41/5.42)) has been performed. The majority of participants used Dynamic Light Scattering (DLS). A few used Electron Microscopy as method (SEM, TEM, T-SEM). Following methods had been applied by only one participant: Small Angle X-ray Scattering, Analytical Ultracentrifugation, Atomic Force Microscopy and Atomizer with electric mobility spectrometer (SMPS). The Task 5.4 of NanoValid is designed to test, compare and validate current methods to measure and characterize physicochemical properties of selected engineered nanoparticles. This will be achieved by inter-laboratory comparisons. The measurand of one of these round robins is <em>Particle size/Particle size distribution.</em> The measurements are to be accompanied by estimates of the uncertainties at a confidence level of 95%, deduced from the standard uncertainties. Therefore an uncertainty budget comprising statistical (Type A) and systematic (Type B) errors has to be established and delivered for each measurand. The inter-laboratry comparison protocol comprises two Annexes addressing the establishment of uncertainty budgets following GUM. The final goal of the comparison is to identify those methods of measurement which have potential as reference methods in pc characterization of nanoparticles for the determination of a given measurand (Task 5.4 of the NanoValid Project).