What is Single Particle Extinction and Scattering (SPES)?

 What is Single Particle Extinction and Scattering (SPES)?

Single Particle Extinction and Scattering (SPES) is a patented method developed by EOS to characterise single particles in fluid mixtures, such as heterogeneous liquids and aerosols. The method provides reliable and meaningful information that is crucial for research and development, quality control, and monitoring of particles in various fluids.

How does the SPES method work?

The SPES method utilises a syringe pump to create a laminar flow of the sample through a tightly focused laser beam. As the particles flow through the narrow waist of the beam between the laser source and a sensor, the method retrieves information about their scattering and extinction. This information is then used to characterise individual particle populations in the mixture, without requiring additional information about their optical properties.

SPES provides valuable insights into particle size distribution, numerical concentration, aggregation, particle loading and optical information, which can be displayed by individual sample components in heterogeneous mixes. This information is crucial for lab-scale design, industrial production, shelf-life optimisation and advanced monitoring of particles in biological, industrial, and environmental fluids.

With the SPES method, fully overlapping particle size distributions for each component material can be analysed. The method also offers a Continuous Flow Analysis mode, where statistical insights can be retrieved for each time frame.

In summary, SPES is a powerful tool for characterising single particles in fluid mixtures. Its reliable and meaningful insights provide valuable information for R&D, quality control, and monitoring applications in various industries.


SPES technology has applications across a range of industries and research sectors. These include:

  • Gold & Silver Nanoparticles
  • Liposomes & Emulsions
  • Encapsulation
  • Drug Delivery
  • Pigments & Inks
  • Environmental Studies
  • Abrasives & Slurries
  • Fine Chemicals
  • Shelf-life optimisation

Discover the Classizer™ One

  • The EOS Classizer™ ONE is a multi-parametric particle analysis platform based on patented Single Particle Extinction and Scattering (SPES) technology.
  • Individual particles are characterised in a continuous liquid flow to obtain detailed information such as optical classification (effective refractive index), particle size distribution and particle concentration – even in samples containing complex heterogeneous particle mixtures.


Contact Us

Complete this form to send us an email and we'll get back to you as soon as possible.

Start typing and press Enter to search