Introduction
The WyattQELS™ is a versatile Quasi-Elastic Light Scattering device designed for use with Multi-Angle Light Scattering instruments. It offers the unique capability to measure correlation functions at various angles, enhancing the study of molecular aggregation and conformational changes.

Specifications
- Size Range: 1 nm to 30 nm in flow mode; up to 0.5 µm in batch mode.
- Measured Volume: 0.2 nl.
- Temperature Control: Ambient, with optional Peltier heater/cooler.
- Data Acquisition: 1-3600 seconds.
- Correlator Minimum Delay Time: 480 nsec.
- Hardware Interface: 248 channel digital autocorrelator with multi-tau distribution.
- Maximum Light Intensity: 10,000,000 photons per second.
- Interface: 1 USB port.
- Operating System: Windows 2000® or Windows XP®.
- Power: 85-265 V, 50-60 Hz input.
- Dimensions: 32 cm x 26 cm x 15 cm.
- Weight: 8.2 kg.

Features and Benefits
The WyattQELS can be used in both flow and batch modes, allowing for the measurement of particle sizes and distributions. It is compatible with DAWN EOS and miniDAWN Tristar systems, enabling simultaneous static and dynamic light scattering measurements. The system is driven by ASTRA software, which processes autocorrelation functions and calculates hydrodynamic radii and diffusion constants.

Software Capabilities
The ASTRA software provides advanced data processing capabilities, including:
- Calculation of hydrodynamic radius and translational diffusion.
- Detection and correction of artifacts.
- Export of results to ASCII files for further analysis.
- Data fitting routines and integrated help files.

Operational Modes
- Flow Mode: Allows for dynamic and classical light scattering data collection, with molar mass and rms radii calculations.
- Batch Mode: Utilizes small sample volumes for complex correlation function analysis, with distribution assumptions for data interpretation.

Special Features
The system includes a micro-cuvette accessory kit for small volume measurements and offers precise temperature control for QELS measurements. The DAWN EOS system allows for measurements at different scattering angles, optimizing data collection time and resolution.

Conclusion
The WyattQELS is a powerful add-on instrument for detailed macromolecular characterization, offering flexibility and precision in light scattering measurements.