Dispersion Stability and Sizing

Optical measurement of particle concentration and
size by static multiple light scattering

  • No sample prep necessary
  • 200x faster than conventional tests
  • Quantification of stability-TSI index computation
  • No mechanical stress applied, natural state analysis
  • Works with concentrated solutions (up to 95% v/v) 


Colloidal Stability analysis and shelf life determination are key criteria in formulation studies of emulsions, suspensions, and foams. TURBISCAN® is the first patented technology to analyze destabilization mechanism in concentrated dispersed media and thus the only to offer accelerated aging tests on the actual unstressed products.


Creaming, sedimentation, agglomeration, aggregation, and coalescence of even highly concentrated formulations are detected, at a very early stage, without dilution nor stress. Stability kinetics analysis is provided for an efficient and reliable analysis of samples and to help evaluate the overall quality of formulations a Turbiscan stability Index can be calculated – quantifying the destabilization with a single number.

TURBISCAN Technology Explained:

SMLS( static multiple light scattering)  is the only technique of stability analysis to offer the advantage of working in concentrated media: It is well adapted for working without dilution and without stress over a wide particle size range: 10 nm – 1 mm at high concentrations (up to 95% v:v).

The emitted light only partially passes through the tube, most are scattered by the particles in the sample. TURBISCAN® detects the intensity of both Transmitted and Backscattered light over the whole tube height. These intensities allow direct monitoring of local physical heterogeneities with a vertical resolution down to 20µm. Thus, nascent destabilization phenomenon (sedimentation or creaming layers, aggregates, agglomerates or coalescence) can be detected and monitored over time at different intervals.

Key Data Provided:

Migration Analysis:

Local variation of light intensity indicates phase formation-
provides the following data:

  • Phase separation kinetics and thickness
  • Sedimentation information
  • Creaming rate
  • Particle migration speed
  • Hydrodynamic diameter

Size Variation Analysis:

Global variation of light intensity corresponds to
size increase providing this information:

  • Size evolution kinetics
  • Mean diameter
  • Agglomeration rate
  • Coalescence rate
  • Dispersibility ratio

TURBISCAN Stability Index

TSI is a Turbiscan specific parameter developed specially for formulators to rapidly, standardize, compare and characterize the physical stability of various formulations.


Any destabilization phenomenon happening in a given sample will have an effect on the Backscattering and/or Transmission signal intensities during the aging process. The formulation with the highest intensity variation, is the one to change in the most significant way, thus the least stable.


The TSI calculation, simple but robust concept, sums up the evolution of T or BS light at all measured position (h), based on a scan-to-scan difference, over total sample height (H):

Thus, for each scan, a single TSI value is associated and “Destabilisation kinetics” graphic can be created showing TSI evolution with time. Below a representative example on 4 samples: 3 new formulations (B, C, D) were compared to an old formulation, considered stable (A).
The Turbiscan provides a quick and global overview of the stability can be established. In a matter of hours, the stability can be evaluated and predicted, days before the changes appear to the naked eye. With a single look at TSI, it is possible to draw conclusions about the most stable formulation.


Here, Sample B offers similar or higher stability than the reference formulation (A). Both Samples C and D are less stable compared to the reference formulation.


For Pre-formulation Applications.

Detects stability evolution at an early stage.


  • Identification and quantification of instability
  • Quick and Reliable
  • Portable and robust
  • Shelf life and long-term stability analysis
  • Migration velocity


R&D, QC, and Analytical Development

Accelerate and document aging tests for fast and deep understanding of your products destabilization mechanisms


  • Identification and quantification of instability
  • Long-term stability analysis simulation
  • Temp range from ambient to 60 °C


Multi-Sample R&D, QC Applications.

Provides 6 independent measurement positions for simultaneous comparison of various formulations.


  • Identification and quantification of instability of up to 6 samples
  • From 4 °C to 80 °C
  • Improved resolution-acquisitions every 20 microns
  • Small bench footprint


High-Throughput Analyzer

Provides automated management of aging test for sample storage at different temperatures


  • Identification and quantification of instability of up to 54 samples

  • From ambient to 60°C
  • Automated, robotic sample handling and storage at multiple temperatures for accelerated shelf life analysis