Wyatt Technology




The world's most advanced light scattering instrument for absolute characterization of proteins, conjugates, macromolecules, and nanoparticles.

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, offering the highest sensitivity and widest range of molecular weight, size and concentrations. It is most often used in conjunction with 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.

  • Overview

    The DAWN HELEOS II and its companion Optilab T-rEX dRI detector are the established benchmarks for MALS analysis, cited in thousands of peer-reviewed publications. With the addition of a ViscoStar II differential viscometer or WyattQELS DLS module, the triple-detection system can analyze molecular conformation and sizes below the rg limit of 10 nm.

    The DAWN may also be used in batch (off-line) mode to characterize the weight-average molar mass, z-average size and second virial coefficient of unfractionated samples.

    • Mw from 200 Da to 1000 MDa
    • Sensitivity: 0.4 µg/mL BSA (66.4 kDa)
    • rg from 10 to 500 nm, up to 1000 nm with shape-specific models
    • Ultra-stable, high-power laser

    In conjunction with a Calypso II CG-MALS system, the DAWN characterizes macromolecular interactions, label-free and immobilization-free: affinity and absolute stoichiometry of self- and hetero-association of simple or complex molecular systems. The Calypso system also automates the determination of second virial coefficients, cross virial coefficients, average molar masses and sizes.


    Temperature-Controlled Models

    • Ambient model
    • Ultra-High-Temperature (UHT) model, from ambient up to +210°C
    • Standard Peltier heated/cooled (H/C) model, temperature control from -15°C to +150°C

    The Ultra-High-Temperature DAWN interfaces with high temperature GPC systems such as the Tosoh EcoSEC GPC-HT or the Polymer Char GPC-IR. View the DAWN-Polymer Char GPC interface, and the DAWN-Tosoh GPC-HT interface.

  • Dynamic Light Scattering

    WyattQELS - A dynamic light scattering (DLS) detection module which integrates inside the DAWN to provide simultaneous DLS measurements in the same scattering volume. The optical collection fiber replaces a MALS detector at any of the 18 detection angles.

    DynaPro NanoStar - Primarily used for batch DLS, the NanoStar does double duty as an on-line DLS detector by installing its optical collection fiber into any of the 18 MALS detectors in the DAWN.

    Ultrasonic Cleaning

    COMET - An ultrasonic transducer that cleans MALS flow cells automatically by agitating the fluid and loosening particles from the glass surfaces. Integrates inside the DAWN.

    Laser Wavelength

    The standard 658 nm red laser may be replaced in the factory with an infrared laser operating at 785 nm. The IR laser minimizes or prevents sample fluorescence to ensure correct molar mass and size measurements on samples that fluoresce under 658 nm excitation. Please This email address is being protected from spambots. You need JavaScript enabled to view it. for available laser wavelengths. Narrow bandpass fluorescence-blocking filters are also available.


    Optical Filters

    Optional polarization or fluorescence-blocking filters may be installed in the DAWN. Fluorescence-blocking filters improve greatly the analysis of samples that fluoresce upon irradiation at the laser wavelength.

  • The DAWN HELEOS II may be positioned downstream of all types of standard GPC, HPLC or FPLC systems for analysis of molar mass and size distributions (see SEC-MALS), and derivatives such as conjugation and conformation analyses, all included in the ASTRA data collection and analysis software. For those systems equipped with a UV, RI, fluorescence or other concentration detector, the DAWN accepts up to 4 analog inputs so a 3rd-party concentration signal may be used in MALS calculations of molar mass. The DAWN is generally set up downstream of a UV detector and upstream of a RI detector.

    In most cases it is beneficial to connect an Optilab T-rEX RI detector to the eluent stream. This permits universal concentration detection regardless of fluorophores or chromaphores. The combination of UV and RI signals, acquired simultaneously, is utilized in ASTRA's Conjugation Analysis algorithm to characterize binary complexes such as glycoproteins, PEGylated proteins, or block co-polymers.

    The DAWN may also be connected to an Eclipse FFF system for characterization of macromolecules and nanoparticles from 1 nm to 1 µm via FFF-MALS.

    Both SEC-MALS and FFF-MALS will benefit from an additional WyattQELS module for measuring nanoparticle size via dynamic light scattering (DLS). The WyattQELS utilizes the same laser and flow cell volume as MALS detection. Its collection fiber replaces any one of the 18 MALS detectors in the DAWN.

    For analysis of natural and synthetic polymers, the ViscoStar II may also be added as well. Differential viscometry is an orthogonal means of determining molar mass and conformation.

  • MALS detectors may be operated in batch mode when the analysis does not benefit from separation:

    • If the sample is not amenable to separation by SEC or FFF (e.g., very large and diffuse polymers such as PMMA) to measure weight-average molar mass, and size as z-average radius
    • In order to validate SEC-MALS measurements:
    • to determine if large aggregates or other species are filtered out on the column
    • to determine if reversible aggregates dissociate subsequent to dilution on the column or separation channel
    • In order to characterize macromolecular or nanoparticle complexes which are disrupted by column shear or dilution
    • In order to measure binding affinity or reaction kinetics of macromolecules such as protein-ligand interactions

    Calypso II - Automated sample preparation and delivery system for carrying out and analyzing composition-gradient MALS in a DAWN. Analyses include biomolecular interactions, high-concentration protein-protein interactions, Zimm plots and dn/dc as well as time-resolved MALS. Utilizes the CALYPSO software for interaction analysis.

    microCUVETTE - Allows static and dynamic light scattering measurements to be made simultaneously in a MALS detector using a quartz cuvette, requiring only 10 µL.

    NanoFilter Kit - Makes it easy to filter, recover and refilter precious sample. This is especially useful when your total sample volumes are below 300 µL.

    Microbatch Kit - Used to inject samples into the flow cell of a MALS detector, and in determining dn/dc with an RI detector.

    Batch Conversion Kit - Inexpensive scintillation vials often suffice when sample volumes aren't an issue, especially if the sample may congeal in the MALS flow cell.

  • Orbit - The Orbit helps conserve mobile phase by programmatically directing the solvent to either a waste bottle or back to the solvent reservoir. In a CG-MALS system, the Orbit is used to automatically choose wash solvents in the post-experiment cleaning cycle.

    SEC Columns - Wyatt offers silica-based columns specifically designed and tested for optimal SEC-MALS measurements of proteins and peptides.

    Solaris - Prevents growth of bacteria, fungi or algae in solvents with high efficiency and protects your system from down-time due to contamination.

    WISH - The Wyatt Injection System High-Pressure (WISH) triggers ASTRA data collection and is ideal for use in SEC-MALS without an autoinjector. Also used with an Optilab dRI detector for the determination of dn/dc values.

    SysTrack - Convenient shelving for holding multiple detectors in your experimental setup.

    Thermos - A temperature-controlled chamber for SEC/GPC columns and FFF channels.

  • ASTRA - Our comprehensive software solution for MALS and DLS analysis in chromatography, AF4 or batch mode, included with each detector. ASTRA is available in a 21CFR(11) compliant version and offers additional options such as particle analysis and a research database.

    CALYPSO - Software for automated composition-gradient MALS experiments: control of the Calypso II, data acquisition and analysis for biomolecular interactions and reaction kinetics as well as weight-average molar mass, z-average molecular size, and virial coefficients.

  • Measurements  
       Molar Mass Range 200 Da to 1000 MDa *
       Molecular Size Range (rg) ≈ 10 to 500 nm, up to 1000 nm with shape-specific models *
       Molecular Size Range (Rh,
       with WyattQELS DLS module or
       DynaPro NanoStar
    Depends on the scattering angle:
    In flow mode, 0.5 nm – 300 nm†*
    batch mode, 0.5 nm – 1 µm *
       Sensitivity 0.4 µg/mL BSA; 0.2 µg BSA typical HPLC loading *
       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 DynaPro NanoStar cuvette-based DLS instrument may be installed in the DAWN.
    Laser Properties  
       Laser Wavelength 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
    Dimensions 60 cm (L) x 36 cm (W) x 23 cm (H)

    * depending on dn/dc, the sample concentration, and chromatography conditions, this is typical.

    assuming a flow rate of 0.3 mL/min and DLS detection at 160°.

    Facilities requirements may be found in Wyatt Instrument Facilities Specifications.
    Host PC requirements may be found in Computer Requirements.

    Specifications subject to change without notice.


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Wyatt Technology is the recognized leader in light scattering instrumentation and software for determining the absolute molar mass, size, charge and interactions of macromolecules and nanoparticles in solution.

Wyatt's line of multi-angle static light scattering products couple to size exclusion chromatography (SEC-MALS), field-flow fractionation (FFF-MALS), and stop-flow composition-gradient systems (CG-MALS). Our dynamic light scattering (DLS) products operate in traditional cuvette as well as on-line and automated, high-throughput modes. We also offer unique instruments for electrophoretic light scattering (MP-PALS), differential refractometry, and differential viscosity.

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