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Malvern Nano ZS Zetasizer

MANUFACTURER Malvern Instruments (manufacturer's website)
MODEL Malvern Nano ZS
AVAILABILITY Official workshop hours are: 9:30 to 12.30 and 13.30 to 16:30 (in practice technicians are often available outside of these times)
CONTACT 1 External enquiries: Martine Dobson - Funding, Development & Support
CONTACT 2 Internal enquiries: Tony Dickson - Principal Technician
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SITE Harris Site


Malvern Nano ZS Zetasizer

The world’s most widely used system. It is used for the measurement of the size, electrophoretic mobility of proteins, zeta potential of colloids and nanoparticles, and optionally the measurement of protein mobility and microrheology of protein and polymer solutions. The high performance of the Zetasizer Nano ZS also enables the measurement of the molecular weight and second virial coefficient, A2, of macromolecules and kD, the DLS interaction parameter.

The system can also be used in a flow configuration to operate as a size detector for SEC or FFF.


The Zetasizer Nano ZS is a high performance two angle particle and molecular size analyzer for the enhanced detection of aggregates and measurement of small or dilute samples, and samples at very low or high concentration using dynamic light scattering with ‘NIBS’ optics. The ZSP also incorporates a zeta potential analyzer that uses electrophoretic light scattering for particles, molecules and surfaces, and a molecular weight analyzer using static light scattering.

Using Non-Invasive Backscatter optics (NIBS) it has significantly better performance than systems using 90 degree scattering optics.

In addition, a microrheology option is available for measuring sample viscosity and viscoelastic properties, as well as a Protein Measurement option for protein mobility measurements.

The flow mode option enables the system to be connected to an SEC or an FFF system to use as a detector for the size of proteins or nanoparticles.

A choice of cuvettes are available, from disposable single-use to specific cells for viscous or high concentration samples or measuring the zeta potential of surfaces.

Parameters measured:

Particle and molecule size, translational diffusion, electrophoretic mobility, zeta potential of particles at high and low concentrations, viscosity and viscoelasticity of protein and polymer solutions, concentration, MW, A2, kD.

An optional accessory enables measurement of the zeta potential of solid surfaces.

  • Size measurement from 0.3nm (diameter) to 10 microns using patented NIBS (Non-Invasive Back Scatter) technology.
  • Zeta potential using patented M3-PALS technology.
  • Molecular weight measurement down to 980Da.
  • Microrheology option to measure viscosity and viscoelasticity.
  • Protein size measurement as dilute as 0.1mg/mL (Lysozyme).
  • Sample concentrations from 0.1ppm to 40%w/v.
  • Optional protein calculators, including protein charge, A2, kD, and molecular shape.
  • A ‘Quality Factor’ and ‘Expert Advice System’ gives the confidence of having an expert at your shoulder.
  • 21CFR part 11 software option to enable compliance with ER/ES.
  • Research software option to give access to further features and analysis algorithms for the light scattering specialist.
  • Automation of measurements using an autotitrator option.
  • Optional flow mode capability to enable use as a GPC / SEC size detector.
  • Alternative laser, 50mW at 532nm for samples incompatible with the standard 633nm laser.
  • Optical filter option to improve measurements with fluorescent sample.
  • Temperature range extension option to 120ºC.

How it works

The Zetasizer Nano ZS incorporates three techniques in a single compact unit, and has a range of options and accessories to optimize and simplify the measurement of different sample types.

Dynamic Light Scattering 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. Non-Invasive Back Scatter technology (NIBS) is incorporated to give the highest sensitivity simultaneously with the highest size and concentration range.

Measurement of size as a function of concentration enables the calculation of kD, the DLS interaction parameter.

The Microrheology option uses the DLS measurement of tracer particles to probe the structure of dilute polymer and protein solutions.

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. This velocity is measured using a patented laser interferometric technique called M3-PALS (Phase analysis Light Scattering). This enables the calculation of electrophoretic mobility, and from this the zeta potential and zeta potential distribution.

A 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 is used to determine the 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 can be calculated, which gives a measure of molecule solubility.

This technique is very demanding on the sensitivity and stability of the whole system, and requires that every element of the design is optimized to ensure accuracy and repeatability.

Image and text courtesy of www.malvern.com


Particle size and molecular size

  • Measurement range: 0.3nm – 10.0 microns (diameter).
  • Measurement principle: Dynamic Light Scattering
  • Minimum sample volume: 12µL
  • Accuracy: Better than +/-2% on NIST traceable latex standards
  • Precision / Repeatability: Better than +/-2% on NIST traceable latex standards
  • Sensitivity: 0.1mg/mL (Lysozyme)

Zeta potential (and optional Protein Mobility)

  • Measurement range: 3.8nm – 100 microns (diameter)
  • Measurement principle: Electrophoretic Light Scattering
  • Minimum sample volume: 150µL (20µL using diffusion barrier method)
  • Accuracy: 0.12µm.cm/V.s for aqueous systems using NIST SRM1980 standard reference material
  • Sensitivity: 10mg/mL (BSA).

Molecular weight

  • Measurement range: 980Da – 20M Da*
  • Measurement principle: Static Light Scattering using Debye plot
  • Minimum sample volume: 12µL (3-5 sample concentrations required)
  • Accuracy: +/- 10% typical

Microrheology (option)

  • Measurement principle: Dynamic Light Scattering
  • Minimum sample volume: 12µL (DLS measurement only) *maximum range, sample dependent


  • Temperature control range: 0°C - 90°C +/-0.1, 120ºC option
  • Light source: He-Ne laser 633nm, Max 4mW.
  • Laser safety: Class 1
  • Power: 100VA at 25ºC

Weight and dimensions

  • Dimensions (W, D, H): 320mm, 600mm, 260mm (W,D,H)
  • Weight: 21 kg

Operating environment:

  • Temperature: 10°C – 35°C
  • Humidity: 35% - 80% non-condensing

Item ID #1509.

Last Updated: 9th November, 2016