Introduction
The WALLIS ȗ is a high-resolution zeta potential analyzer designed for characterizing nanoparticle suspensions. It utilizes an advanced version of the Laser Doppler Electrophoresis (LDE) technique, offering unmatched measurement resolution. This device is complementary to Cordouan’s VASCO particle size analyzer for studying colloidal solution stability and properties.

Zeta Potential Measurements
Zeta potential (ζ) is a critical property of colloidal suspensions, related to the electrical charges on particle surfaces in a solvent. It influences particle interactions and formulation stability, described by models like the Electrical Double Layer (EDL).

Measurement Principle
The WALLIS ȗ applies an electrical field between electrodes in a colloidal suspension, causing charged particles to move (electrophoresis). The speed of this motion is proportional to the electrical field, determined by measuring the Doppler frequency shift using a high-sensitivity optical heterodyne interferometer.

Measurement Cell Design
The design is simple, robust, and artifact-free. The dip cell allows easy sample preparation and prevents bubble formation. It is compatible with standard cuvettes made of polystyrene, glass, or quartz. The vitreous carbon electrodes are durable and easy to clean, preventing artifacts like electro-osmosis effects.

Specifications
- Zeta potential range: -500 mV to 500 mV
- Mobility range: 10^-10 to 10^-7 m²/V.s
- Particle size: 1 nm to 100 µm
- Sample concentration: 0.0001% to 10% w/%
- Temperature control: 10°C to 70°C
- Sample volume: Typically 750 µL
- Maximum sample conductivity: 300 mS/cm
- Compatible with aqueous and organic solvents, pH 1-14

Key Benefits
- No electro-osmosis, artifact-free measurements
- Improved LDE technology for efficiency and reliability
- Enhanced resolution, 10 times better than usual correlation technology
- Accurate and repeatable zeta potential analysis
- Easy-to-use GUI software
- Long-life electrodes reduce maintenance costs
- Compatible with standard disposable and quartz cuvettes

Applications
The WALLIS ȗ is suitable for various applications, including functionalization studies, drug delivery optimization, quality control in manufacturing, and advanced colloidal stability analysis.

System Compliance
The device is CE certified, compliant with ISO 13099-2:2012 for zeta-potential determination using optical methods.

Contact Information
For more information, contact Cordouan Technologies at [email protected] or visit their website at www.cordouan-tech.com.