The ability to quickly and economically characterize particle samples is increasingly important. A knowledge of particle size distributions can be critical in a wide variety of processes, from powder metallurgy to ethical drug delivery. Powdered materials may be contaminated at levels of only one particle in one thousand and still be unsuitable for use. Particulate samples may represent a variety of materials from many sources, requiring complex analyses for complete characterization. The traditional analytical approach to these problems, dictated by the need for economy, has been the application of batch techniques (e.g. light scattering) to the problem of particle sizing and trace component and bulk techniques (e.g. atomic absorption, x-ray fluorescence) to the problems of particle analysis. Scanning electron microscopy (SEM), combined with energy-dispersive x-ray spectrometry (EDS), is capable of directly measuring the required individual particle sizes, morphologies and compositions but has not been widely applied due to the high cost of analysis of several hundred to thousands of particles which may be required to adequately represent an entire population.
Laser-induced convection shifts size distributions in nanoparticle tracking analysis