Comparing the backscattering intensity using blue and IR light sources in dispersion stability analysis

Dispersions are encountered in everyday life in many different products, ranging from salad dressings and cocktails in the food sector, emulsions and creams in cosmetic and pharmaceutical products to multi-phased cleaning agents, emulsion paint or seal slurry in the building industry, to name just a few examples. For all these products the dispersion stability is an extremely important factor that has to be analysed and optimised during product development. The MultiScan technique is a powerful tool to quantify stability issues in dispersions. Traditionally this technology relies on IR light which works very well in most cases. However, the measured signals can be very low when the samples have a low concentration and especially if they are composed of nano particles. In this case, the signal to noise ratio can be low resulting in a negative influence on the accuracy of the destabilization analysis. To solve this problem, DataPhysics Instruments developed a stability analyser utilising blue light. In this application note, commercial polymer microsphere suspensions with various particle sizes and concentrations are used to compare the signal quality of the analyser using blue light with the system using IR light.