Dynamic light scattering instrument measuring zeta potential, particle size, and electrophoretic mobility for colloidal stability and surface charge characterization.
The DataPhysics ZPA 20 combines dynamic light scattering (DLS) and electrophoretic light scattering (ELS) to simultaneously measure particle size, zeta potential, and electrophoretic mobility of colloidal dispersions. It provides the essential data for understanding colloidal stability, optimizing surface coatings, and formulating stable dispersions.
The DataPhysics ZPA 20 is a combined dynamic light scattering (DLS) and electrophoretic light scattering (ELS) instrument for the complete characterization of colloidal dispersions. DLS measures the hydrodynamic diameter of nanoparticles and colloids from the temporal fluctuations of scattered laser light caused by Brownian motion. ELS measures the electrophoretic mobility of charged particles under an applied electric field, from which the zeta potential is calculated using the Henry or Smoluchowski equations.
Zeta potential is the key indicator of colloidal stability: dispersions with |ζ| > 30 mV are generally considered electrostatically stable, while values near zero indicate prone-to-aggregation systems. The ZPA 20 enables systematic pH zeta potential titrations and ionic strength studies to map the stability diagram of complex dispersion systems.
The instrument uses a low-volume disposable cuvette (< 1 mL), minimizing sample consumption and cross-contamination risk. A Peltier temperature control unit maintains precise temperature from 2°C to 90°C for temperature-dependent studies and measurement at physiologically relevant conditions.
| DLS Size Range | 0.3 nm – 10 µm |
| Zeta Potential Range | –200 mV to +200 mV |
| Electrophoretic Mobility | –20 to +20 µm·cm/(V·s) |
| Laser | 532 nm or 633 nm diode laser |
| Scattering Angle | 173° (backscatter, standard) |
| Temperature Range | 2°C – 90°C (Peltier) |
| Sample Volume | < 1 mL (disposable cuvette) |
| Conductivity Range | 0 – 200 mS/cm |
| Measurement Time | 2 – 5 min (zeta) / 1 – 3 min (size) |
| Software | ZPA (Windows), ISO 13099 reporting |
| pH Range | 1 – 13 |
| Standards | ISO 13099-2, ISO 22412 |
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