Combined imaging and chromatic confocal microscopy technique to characterize size and shape of ensembles of cuboidal particles

The presence of needle- and plate-like particles has detrimental consequences on their downstream processing in the fine chemicals sector. Therefore, the ability to accurately characterize the particle size and shape is essential to quantify and predict their impact on the product processability. Nonetheless, tools to characterize both the size and shape of ensembles of cuboidal particles are seldom available. The overarching goal of this work is to provide a fast and accurate offline size and shape characterization tool. To this aim, we have designed and experimentally validated a combined imaging and chromatic confocal microscopy technique. We propose two modes of operation: one that facilitates the accurate 3D reconstruction of particles; and the other that facilitates their rapid characterization. We validate the performance of our technique using a commercial technique. We show that our technique can accurately characterize thousands of particles, making it a valuable addition to existing process analytical technology.