The Zetasizer Ultra is the world’s most capable combined DLS and ELS system, incorporating Non-Invasive Back Scatter (NIBS®) and, uniquely, Multi-Angle Dynamic Light Scattering (MADLS) technology for the measurement of particle and molecular size. NIBS provides the versatility and sensitivity to measure over a wide concentration range, while MADLS permits a higher resolution view into your sample’s size distribution for those critical measurements.

An extension to MADLS affords the ability to directly analyze particle concentration. The measurement of particle concentration is calibration-free, suitable for a wide range of materials, requires no or little dilution, and is quick to use – all of which make it ideal as a screening technique.  This is a unique capability of the Zetasizer Ultra which can even be applied to samples such as viruses and VLPs, which were previously very challenging to measure. 

The Zetasizer Ultra also provides the highest sensitivity zeta potential and electrophoretic mobility measurements using M3-PALS technology.  Our affordable disposable folded capillary cells enable measurements in extremely low volumes, without direct sample-electrode contact, using our patented diffusion barrier method.  The information provided by these measurements is an excellent indicator of sample stability and/or propensity to aggregate.

The addition of Constant Current Mode for measuring electrophoretic mobility and zeta potential in high conductivity media reduces errors that can be associated with electrode polarization at higher ion concentrations.

The Zetasizer Ultra incorporates two technologies in a single compact unit, with a range of options and accessories to optimize and simplify the measurement of different sample types.

Dynamic Light Scattering (DLS) is used to measure particle and molecule size. DLS measures the diffusion of particles moving under Brownian motion and converts this to particle size and particle size distribution using the Stokes-Einstein relationship. Non-Invasive Back-Scatter (NIBS) technology is incorporated to give the highest sensitivity within the broadest range of sizes and concentrations. DLS is a highly flexible sizing method which is rapid, accurate and repeatable. It requires only small volumes of sample for analysis, and is non-destructive. This technique is material-independent and therefore extremely widely applicable.

Multi-Angle Dynamic Light Scattering (MADLS) is also incorporated in the Zetasizer Ultra, to offer the highest resolution and angular-independent size distribution analysis. MADLS also enables the simple, calibration-free measurement of particle concentration in homogeneous sample types, covering a wide range of materials.

Electrophoretic Light Scattering (ELS) is used to measure zeta potential. An electric field is applied to a solution of molecules or a dispersion of particles which move with a velocity related to their charge. 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 of a sample.

The use of ELS commonly relates to stability and formulation applications. Particles or molecules with no net charge may bind together, which may be a challenge in systems such as protein formulations which are prone to aggregation. Particles or molecules which have either a net positive or net negative charge will better maintain a distance from one another, creating a stable system. The formulation containing these particles or molecules is very influential on their charge state, and changes to formulation attributes such as pH, additive concentration and ionic concentration can impact product stability and shelf life.

ZS Xplorer Software Suite

The software is designed to be very easy to use, even whilst enabling the rapid construction of complex methods. Information on the sample, its conditions, and the variables to be tested are entered at the beginning of a run, and ZS Xplorer uses this information intelligently to optimize the method for that sample. A deep learning empowered data quality guidance system provides feedback on results and offers clear advice on how data may be improved if required.


The MPT-3 Auto titrator enables study of the effect of changes in pH.

A range of disposable and reusable cells are available to optimize the measurement in terms of sample volume and concentration, including the new low volume disposable sizing cell kit, which offers the dual benefits of size measurements in as little as 3uL, and extension to the upper size range of DLS measurements, due to the suppression of convection currents.

Particle size and molecular size

Measurement principle:
Dynamic light scattering (Non-Invasive Back-Scatter - NIBS)
Dynamic light scattering (13°, 173°)
Multi-Angle Dynamic Light Scattering (MADLS)
Measurement angle:
173°, 13°, 90° ¹
Measurement range:
0.3 nm - 10 μm (diameter) ²
Minimum sample volume:
3 μL
Concentration range:

Minimum sample concentration ³: 
NIBS (173°):
0.1 mg/mL 

Forward angle (13°):
5 mg/mL 

Side angle (90°):
1 mg/mL 

1 mg/mL

Maximum sample concentration ⁴ ⁵: 
40% w/v 

Zeta potential

Measurement principle:
Mixed-mode measurement, phase analysis light scattering (M3-PALS)
Size range:
3.8 nm – 100 μm (diameter) ²
Minimum sample volume:
20 μL ⁶
Concentration range:
1 mg/mL ³ - 40% w/v ⁴ ⁵
Sample conductivity range:

Maximum: 260 mS/cm
Accuracy: ± 10%

Particle concentration

Concentration range:
30nm gold: 1 x 10⁸ - 1 x 10¹² particles/mL


Avalanche photodiode
Temperature control range:
Purge facility using dry air/nitrogen ⁷
Dimensions (W, D, H):
322 mm x 565 mm x 245 mm
19 kg
AC 100-240 V, 50-60 Hz, 4.0 A
Power consumption:
Max. 100 W, 45 W typical
Ambient conditions:
+10°C to +35°C (+50°F to +95°F) 35% - 80% RH (non-condensing)
USB 2.0 or higher



1. Water as sample dispersant;
2. Peak mode range (diameter) 0.6 nm - 10 μm; sample & sample preparation dependent;
3. Measured using 15 kDa protein;
4. Sample-dependent;
5. Measured using bile acid;
6. Using diffusion barrier method;
7. Temperature accuracy 0.1°C at 25°C, 0.2°C at 0°C, 0.5°C at 90°C, 2.5°C at 120°C

Zetasizer Ultra

Zetasizer Ultra accessories

SV-10 viscometer

Viscosity measurement with speed, simplicity and accuracy.


The SV-10 measures viscosity with the accuracy required for dynamic light scattering, for the conversion of diffusion speed to size, and electrophoretic mobility to zeta potential, in an extremely simple and rapid system.

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Cell and cuvette options

Disposable folded capillary cell (DTS1070)

Eliminate sample cross contamination between zeta potential measurements using a completely disposable cell.


The zeta potential of colloids and molecules is extremely sensitive to contamination from components of a previous sample used in a measurement cell. The use of a disposable cell completely eliminates this potential contamination issue.

The folded capillary cell provides the benefits of the accuracy of measurement of a capillary cell with the ease of use of a disposable cell.

Although, disposable, including the electrodes, for low conductivity samples each cell can be used for hundreds of measurements if required.

The cell can be used with the autotitrator, where multiple measurements are routinely done over a wide pH range.

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Universal 'dip' cell kit

Reusable solvent resistant cell.

The dip cell is used for the measurement of zeta potential of samples in aqueous and non-aqueous dispersants, and is designed to be cleaned and reused. It is for batch measurements using standard polystyrene or glass cuvettes.
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High concentration zeta potential cell kit

Save time and effort by measuring zeta potential with little or no dilution.


The high concentration cell enables the measurement of the zeta potential of samples with little or no dilution in any Zetasizer Nano system that measures zeta potential.

The cell has a flow configuration so can be used for stop-flow size and zeta potential measurements using an MPT-2 autotitrator as well as batch measurements.

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12mm square glass cell (PCS8501)

Glass cuvette for batch measurements.

  • For size and molecular weight measurements.
  • Compatible with aqueous and non-aqueous solvents and dispersants.
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12mm Glass cell (PCS1115)

Glass cuvette for use with the dip cell.

  • For size and zeta potential measurements using the ‘dip’ cell.
  • Compatible with aqueous and non-aqueous solvents and dispersants.
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Low-volume quartz batch cuvette (ZEN2112)

Low-volume quartz batch cuvette for size and molecular weight measurements.

This quartz cuvette holds between 12 μL and 45 μL of sample and is used for size measurements. It is compatible with both aqueous and non-aqueous solvents and dispersants.

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12mm Square Polystyrene Cuvettes (DTS0012)

Disposable polystyrene cuvettes.

  • 100 disposable cells complete with 100 stoppers to avoid cross contamination.
  • For size measurements using aqueous dispersants.
  • Compatible with zeta potential measurements using the dip cell.
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Disposable Solvent Resistant Micro Cuvette (ZEN0040)

Disposable plastic micro cuvette, for size measurement at 173° (NIBS) optics only.

  • 100 x 40µL cuvettes with 100 caps to avoid cross contamination.
  • Compatible with aqueous samples and a range of other solvents: Acetone, Benzaldehyde, Butanone, Dioxane, DMF, Ethyl acetate, Isopropanol, plus various acids and bases.
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  • Multi-Angle Dynamic Light Scattering (MADLS) scheme for absolute confidence in particle and molecular size distribution analysis
  • NIBS optics for versatile, high sensitivity, particle and molecular size measurements
  • Simple, calibration-free particle concentration measurements
  • Disposable capillary sizing cell provides the ultimate in non-destructive, low volume (down to 3 µL) analysis, with an upper size range that extends to 10 μm
  • M3-PALS with Constant Current Mode for zeta potential and electrophoretic mobility measurements
  • ZS Xplorer software suite for simple and flexible method set-up and data analysis
  • Adaptive Correlation for faster, more reproducible sizing measurements with less sample preparation
  • Deep Learning empowered data quality system for assessment of any size data quality issues, with clear advice on how to improve results
  • Optical filter wheel with fluorescence filter to allow measurement of fluorescent samples without impairing overall system sensitivity.  Also includes polarization filters for DDLS measurements.