In‐line Comparison of Particle Sizing by Static Light Scattering, Time‐of‐Transition, and Dynamic Image Analysis

Abstract

AbstractParticle size analysis is important in both process and quality control. Different techniques are currently available. In this contribution, the characteristics of three techniques, based on Static Light Scattering (SLS), Time‐of‐Transition (TOT), and Dynamic Image Analysis (DIA), are compared using various aqueous dispersions. Hereby, the techniques were connected in series, so that simultaneous measurements could be performed on the same sample. The experimental results demonstrated that each of the investigated techniques has its strengths and limitations. Thus, SLS results may be largely affected by the choice of the refractive index of the dispersed particles as well as by the choice of the inversion algorithm to convert the angular spectrum to a particle size distribution. As neither TOT or DIA require information concerning the (complex) refractive index of the particles and are based on the detection of individual particles, these techniques are claimed to be very useful for measuring particles in the micrometer size range, although the measurement can be heavily affected by the particle transparency and concentration. Furthermore, all the techniques appear more suited to discerning small particles within a population of large particles than to detecting large particles within a population of small particles. Finally, TOT is much less sensitive towards submicron particles, as compared to SLS. The latter technique does not only have a broader dynamic range, which extends down to the submicron range, but also produces reliable results at higher sample concentrations as compared to TOT and DIA.