Technique Analyte form Size of nominally 10nm particles (nm) Size of nominally 30 nm particles (nm) Size of nominally 60 nm particles (nm) ES-DMA Dry, aerosol 11.3 ± 0.1 28.4 ± 1.1 56.3 ± 1.5 TEM Dry, on substrate 8.9 ± 0.1 27.6 ± 2.1 56.0 ± 0.5 DLS (a) Diluted liquid suspension 13.5 ± 0.1 28.6 ± 2.1 56.6 ± 1.4 DLS (a) Diluted liquid suspension 13.5 ± 0.1 26.5 ± 3.6 55.3 ± 8.3 AEM Dry, on substrate 8.5 ± 0.3 24.9 ± 1.1 55.4 ± 0.3 SEM Dry, on substrate 9.9 ± 0.1 26.9 ± 0.1 54.9 ± 0.4 SAXS Native liquid suspension 9.1 ± 1.8 24.9 ± 1.2 53.2 ± 5.3

Table 3: Mean diameter and expanded uncertainty average particle diameter of gold nanoparticles [adapted from, NIST certificate, 2007]. DLS results: (a) 173° scattering angle, (b) 90° scattering angle. The uncertainties represent repeatability not the width of the particle size distributions [36].