Preliminary study on nanoparticle sizes under the APEC technology cooperative framework

Despite the fact that there exist several techniques capable of characterizing nanoparticle sizes, their measurement results from the same sample often deviate from each other by an amount that is considered significant on the nanometre scale. In the absence of international standards, or worldwide recognized protocols dealing with nanoparticle characterization, an APEC-led preliminary interlaboratory comparison on nanoparticle size characterization was carried out among ten laboratories from six member economies. Test samples of nanoparticles of 20 nm and 100 nm nominal sizes were distributed for measurements by dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microcopy (AFM) and differential mobility analyser (DMA). The comparison result showed fair agreement among the measurements on the certified reference materials (CRM) of 20 nm and 100 nm nanoparticles. Greater deviation was observed on the 20 nm nanosilver colloid sample. This comparison was regarded as a preliminary study on the measurement consistency among various nanoscale measurement techniques.