Analysis of Dye-covered Nanoparticles

This application example looks at the EDS analysis of SiO2 nanoparticles covered with an organic dye at highest magnification using the XFlash® FlatQUAD. (Sample courtesy: S. Rades, K. Natte, T. Behnke, BAM Federal Institute for Materials Research and Testing, Berlin, Germany). The research leading to these results has received partial funding from the European Union Seventh Framework Programme (FP7/2007–2013) under grant agreement no. 263147 (NanoValid – Development of reference methods for hazard identification, risk assessment, and LCA of engineered nanomaterials).


The first image is a secondary electron image showing several agglomerates of nanoparticles at roughly 100,000x magnification. The green rectangle indicates the area mapped with the XFlash® FlatQUAD.

Second image is a mixed element map of an agglomerate of 3 nanoparticles. Map size is 250 × 250 pixels, HV was 5 kV, beam current 520 pA, acquisition time 391 s.

Third image is a mixed map of Si and O, measurement parameters as before.

Fourth image is a single element map of carbon in false color coding to emphasize the intensity of radiation, measurement parameters as before. The organic dye covering the nanoparticles can be clearly recognized by its reddish/pinkish color, indicating the highest carbon intensity in the map. Also, it seems that dye has leached from the particles, spreading on the substrate, recognizable as a greenish patch close to the particles. This patch is also visible in the first and second image. It is most likely an effect of preparing the sample onto a carbon TEM membrane.