Automated Particle Analysis by Microscopy, A Primer

Extract

Questions about samples consisting entirely of a collection of microparticles come from people involved in a wide variety of industries dealing with powders, from Pharmaceuticals to industrial minerals, powdered coatings to industrial hygiene concerns. The questions often asked are morphological. How big? How long? How wide?, and often pose a special problem for the microscopist. The time and tedium associated with answering these questions for a significant subset of the sample particles without an automated system causes the cost to skyrocket and sends the requester off to the light scatterers who at least give cheap answers, never mind that nobody knows what they really mean (What is the average size of a particle with an aspect ratio of 5? And did you calibrate your scattering system for my particles in my dispersant or are you still using latex spheres in water?). A common additional question is “How many are quartz, or titania, or organic, or….?” The inherent advantages of microscopy—the ability to determine detailed morphology in two dimensions (and maybe three), and to discriminate different particle types in a mixture—were usually overwhelmed by the cost and time involved.