Measurement of microparticle size and size distributions is a critical and challenging task to anyone who is working with micron and sub-micron materials. Many different methods exist to complete this task (Figure 1). As with all analytic techniques, the best choice is application specific. The most critical aspect of microparticle sizing is the use of microparticle size standards. In some cases, the use of a standard is required to verify the correct operation of a sizing instrument; in others, the instrument must be calibrated with a series of size standards before accurate measurements can be produced.
Polysciences provides Precision Particles, a series of NIST traceable polystyrene microparticle size standards that range in size from 40 nm to 175 µm. Standards are supplied as 1% solids suspensions in de-ionized water with surfactant.
Because of the many different and acceptable sizing techniques used (Figure 1), it is important for the end user to know how Polysciences determines particle size.