Dynamic Light Scattering (DLS)
DLS is a robust, straightforward, and non-contact method for measuring particle size and particle size distributions in the nanometer to submicron range.
With high sensitivity, it is ideally suited for detecting size changes over time, allowing for real-time tracking of process modifications that occur within seconds.
Photon Correlation Spectroscopy (PCS) as Conventional Technology
The principle of DLS is traditionally implemented using PCS. A laser is transmitted through the sample, and the scattered light intensity is monitored over time using a photodetector, followed by autocorrelation analysis. The particle size distribution is calculated from the correlation function.
Size analysis with PCS is valid only for single scattered light. Samples with high solid concentrations exhibit a significant proportion of multiple scattered light, which limits the effectiveness of this method.
Samples must be diluted to a high ratio to avoid inaccurate particle distribution data and to generate reliable measurement results, which may lead to significant alterations in particle properties.
Photon Cross-Correlation Spectroscopy (PCCS) as Key Technology
By utilizing an innovative light scattering technique known as PCCS, concurrent measurements of particle size and stability in opaque suspensions and emulsions is possible.
The exceptional technical features of 3D cross-correlation include the acquisition of two separately generated scattered light intensities and their cross-correlation. This process separates the single scattered light component from the multiple scattered component.
A single laser beam is divided into two beams of identical intensity and superimposed within a single sample. Two independent scattering waves are recorded with separate detectors for each wave, ensuring precise signal interpretation.
NANOPHOX with PCCS
As a leading innovator in PCCS technology, Sympatec has produced the first tabletop instrument based on PCCS. This development aligns with their strategy of creating innovative instruments that measure samples as closely as possible to their original state.
PCCS enables the analysis of nanoparticles in suspensions and emulsions at solid concentrations hundreds of times higher than previously achievable.
Source: Sympatec GmbH
| Specifications | Quality of measurement results |
| Sensor |
NANOPHOX |
| Overall measuring range |
0.5 nm - 10,000 nm |
| Measuring principle |
| Dynamic light scattering (DLS) |
Acquisition of scattered light intensities of particles in suspension under thermal motion (Stokes-Einstein equation) at 90° |
| Photon cross-correlation spectroscopy (PCCS) |
3D cross-correlation
- Illumination of the same measuring volume by two separate laser beams
- Intensity fluctuations recorded by two independent detectors deploying identical scattering vectors
- Cross-correlation of the two separately acquired intensity patterns to determine particle size
- Elimination of multiple scattering effects
- In accordance with ISO 22412
|
| Photon correlation spectroscopy (PCS) included |
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This information has been sourced, reviewed and adapted from materials provided by Sympatec GmbH.
For more information on this source, please visit Sympatec GmbH.