General method of specimen preparation for the quantitative microscopic characterization of nano- and microparticles

Highlights: • Aggregated magnetic nanoparticles are broken down to its constituent particles and fixed on a sample carrier for microscopy. • Quantitative analysis of particle systems with computer-assisted image analysis of microscopic images is achieved. • Nanoparticle impurities in microparticle samples could be revealed. • Primary particle distributions based on a mathematical model are calculated. -- Abstract: Nano-materials are a subject of current research and development due to their special characteristics, based on the size of their constituent particles. A major hurdle is the reliable analysis of the particle size and particle size distribution. This article introduces a new method of specimen preparation for the quantitative analysis of particle systems. Selected examples show the capabilities of computer-assisted image analysis of microscopic images. The problem of agglomeration and aggregation of primary particles is discussed and a strategy for calculating the primary particle distribution based on a mathematical model is presented. The successful, highly controlled deposition of deagglomerated nanoparticles on a microscope carrier enables a reliable particle size distribution measurement, even with strong interacting nanoparticles.