The DAWN® HELEOS® II is the premier Multi-Angle static Light Scattering (MALS) detector for absolute characterization of the molar mass and size of macromolecules and nanoparticles in solution. The DAWN offers the highest sensitivity, the widest range of molecular weight, size and concentration, and the largest selection of configurations and optional modules for enhanced capabilities.

The DAWN is most often used in conjunction with Gel Permeation Chromatography (GPC-MALS) or Size Exclusion Chromatography (SEC-MALS) or Field-Flow Fractionation (FFF-MALS) to determine distributions of mass, size and composition independent of column calibration by reference standards.

Included with each DAWN is a copy of ASTRA, the most versatile software package available for analysis of online multi-angle and dynamic light scattering.

For more information, please visit:


Molar Mass Range 200 Da to 1000 MDa1
Molecular Size Range (rg) ≈ 10 to 500 nm1, up to 1000 nm with shape-specific models
Molecular Size Range (Rh, with WyattQELS DLS module or DynaProNanoStar) Depends on the scattering angle:
In flow mode, 0.5 nm - 300 nm1,2
batch mode, 0.5 nm - 1 µm1
Sensitivity 10 ng of 100 kDa polystyrene in THF3 200 ng of BSA in PBS4
Mobile Phase Compatibility All-solvent compatible (aqueous and organic). Wetted materials are 316 stainless steel, fused silica or F2 glass, and Kalrez.
MALS Detectors High-gain, high dynamic range, static light scattering detectors at 18 angles.
Auxiliary Detectors Laser monitor for stabilization feedback; forward transmission monitor to correct signals for absorbing samples and to assess data quality.
A/D Resolution 24 bit (detector dynamic range > 16,000,000)
DLS Detector (optional) WyattQELS dynamic light scattering module installs directly inside the DAWN chassis.

Alternatively, the optical fiber pickup of the DynaProNanoStar cuvette-based DLS instrument may be installed in the DAWN.
Laser Properties
Laser Wavelength 658 nm; 785 nm available for fluorescence reduction (with lower sensitivity than 658 nm)
Laser Power Control Programmable 10% - 100%
Flow Cells Fused Silica, optimal for solvent refractive index less than 1.50 F2, optimal for solvent refractive index above 1.50
Temperature Options Ambient
Heated/Cooled (HC) -15°C to +150°C
Ultra-High-Temperature (UHT) ambient to +210°C
Analog Inputs 4 differential analog inputs with 24 bit resolution. Input range -10 V to +10 V
Analog Outputs 2 analog outputs from user settable measurements channels -10 V to +10 V
Other Inputs/Outputs Alarm in, Alarm retransmit, Auto-Inject in, Auto inject contact closure, Recycle in, Recycle valve power
Computer Interface Ethernet
Transmission Rate 36.6 to 0.0001 Hz
Front Panel Display 162.5 mm, 16-bit, high resolution touch screen displays signal graphs, instrument settings and diagnostics
1Typical. Actual range depends on dn/dc, sample concentration, sample conformation and chromatography conditions.

2Upper limit assumes a flow rate of 0.3 mL/min and DLS detection at 160°.

3Under HPLC-SEC conditions with 7.8x300 mm GPC columns.

4Under HPLC-SEC conditions with Wyatt 7.8x300 mm SEC protein columns.

Host PC requirements may be found in Computer Requirements.