Bio2 - Particle analysis

Particle size and shape

The TurbiScan MA 2000 (light source l= 850 nm) instrument measures the scattering of light from sample in two ways: The change in transmission light through the sample and the intensity of light scattered at angle 45° with respect to the incident beam (back scattering). Using transmission and back scattering, it is possible to detect the stability of the sample (sedimentation, creaming, flocculation, coalescence and phase separation). It is also possible to calculate a particle size, a density and a volume fraction. TurbiScan allows the analysis of physical destabilization of concentrated (up to 50 %) and dark dispersions. Analysis it is not limited by the shape or size of the particles.

Mastersizer (Malvern Mastersizer 2000) works by using the optical bench to capture the actual scattering pattern from a field of particles. Then, using the theories: Fraunhofer model and Mie theory, it calculates the size of particles that created that pattern.

Particle potential and charge

Electrophoretic mobility (The Coulter Delsa 440 Doppler Electrophoretic Light Scatter Analyzer): The instrument is a laser-based multiple angle particle electrophoresis analyzer. Using Doppler frequency shifts in the dynamic light scattering from particles, the instrument measures the electrophoretic mobility (or zeta potential) distribution together with the hydrodynamic size of particles (size range 10 to 30 µm) in liquid suspensions by photon correlation spectroscopy. The instrument has a 256 channel digital correlator.

Potentiometric titration: The instrument is available for high-precision potentiometric titration of macromolecules and surfaces. They can perform fully automated coulometric or volumetric titration (stability ± 10 V) with stability checking. The data are analysed with the LETAGROPVRID, FITEQL and SOLGAS programs.

Polyelectrolyte titration: There is also equipment for polyelectrolyte titration of surface charge and dissolved macromolecules using spectrophotometric determination of the end point or Mütek PCD 03 in the department.

Zetasizer (Malvern Zetasizer Nano-ZS90) analyser measures particle and molecule size from below a nanometer to several microns using dynamic light scattering, zeta potential and electrophoretic mobility using electrophoretic light scattering, and molecular weight using static light scattering.

This service is provided by:

Department of Bioproducts and Biosystems

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