Products as diverse as cosmetics, paints and inks, and drugs and polymer latexes all depend upon the dispersion of particles in a liquid phase. To produce these colloidal dispersions accurately and ensure that they perform according to specification, particle size needs to be monitored during manufacturing and as part of quality control of the final product. A technique that quickly and accurately determines particle size is dynamic light scattering (DLS), and Brookhaven Instruments Corporation was one of the first companies to develop a particle sizing instrument based on this technique. Today, the 90Plus Particle Size Analyzer is one of the company’s most popular instruments.
Particle size is an important parameter in the development of new polymers, something the Department of Chemistry at the University of Cyprus needs to assess if methacrylate polymers have potential as drug delivery systems. The 90Plus system has allowed the laboratory to determine the micellar hydrodynamic sizes of methacrylate polymers in water and organic solvents, allowing amphphilic block copolymer-based networks to be compared for size and performance.
Finally, it is not just the instrument’s particle sizing ability that impresses its users. The flexibility to upgrade or add other features, such as zeta potential option and high power lasers for weakly scattering particles, also rates highly with them. One such user is Charanjit Saini, a graduate polymer chemist in the polymer chemistry department at the Dionex Corporation, California. The department’s existing instrument was upgraded to a 90Plus system so the particle size and polydispersity of latexes used to produce chromatographic stationary phases could be determined. The upgraded system has a BI-Zeta option and a BI-SM50 small volume cell, which allows the amount of sample Charanjit used to be reduced from 2.3 mL to just 50 µL.