The *Zetasizer Nano ZS* incorporates three techniques in a single compact unit:

*Dynamic Light Scattering (DLS)*is used to measure**particle and molecule size**. This technique measures the diffusion of particles moving under Brownian motion, and converts this to size and a size distribution using the Stokes-Einstein relationship. Measurement of size as a function of concentration enables the calculation of**k**_{D}**, the DLS interaction parameter**.*Laser Doppler Micro-electrophoresis*is used to measure**zeta potential**. An electric field is applied to a solution of molecules or a dispersion of particles, which then move with a velocity related to their zeta potential. An available surface zeta potential accessory uses tracer particles to measure electro-osmosis close to a sample surface to calculate the**zeta potential of the surface**.*Static Light Scattering***molecular weight**of proteins and polymers. In this technique, the scattering intensity of a number of concentrations of the sample is measured, and used to construct a Debye plot. From this the average molecular weight and**second virial coefficient A**_{2 }can be calculated, which gives a measure of molecule solubility.

**Specifications:**

**Particle size and molecular size**

- Measurement range: 0.3 nm – 10.0 µm (diameter)
- Minimum sample volume: 12 µL
- Sensitivity: 0.1 mg/mL (Lysozyme)

**Zeta potential**

- Measurement range: 3.8 nm – 100 µm (diameter)
- Minimum sample volume: 150 µL (20 µL using diffusion barrier method)
- Sensitivity: 10 mg/mL (BSA)

**Molecular weight**

- Measurement range: 980Da – 20M Da*
- Minimum sample volume: 12µL (3-5 sample concentrations required)
- Accuracy: +/- 10% typical

**General**

- Temperature control range: 0°C – 90°C +/-0.1
- Light source: He-Ne laser 633nm
- Laser safety: Class 1