Malvern Instruments ZetaSizer HPPS is a non-invasive technique and provides information about size and PSD of particles and molecules dispersed and dissolved in a liquid.
The instrument has a laser light source which is used to illuminate the particles. Then, the generated scattered light fluctuates at a speed depending on the particle size. With the velocity of the Brownian motion, derived from the analysis of these fluctuations, and the Stokes-Einstein equation, particle size can be obtained.
Particles lower than 1nm in size can be analysed by using this instrument and the minimum sample volume requirement is 20µL.