Combining the backscattering intensities of blue and IR light sources to get a uniquely defined mean particle size

The particle size is a key parameter when producing particulate materials owing to its dominant effect on various product properties. Thus, particle size determination is of high interest in many fields, such as cosmetic, chemistry, pharmacy, and food industry. As reported, the mean particle size can be easily computed based on Mie theory using the Multiscan technique. However, Mie theory most often gives two values of mean particle size, which impedes the applicability of the method. To solve this problem, DataPhysics Instruments developed a stability analyser utilising blue light. In this application note, commercial polymer microsphere suspensions with two different particle sizes and concentrations are used as examples to show that a uniquely defined mean particle size can be obtained by utilising the analyser with blue light working together with the existing system with IR light.