Wyatt Technology
  • Another path to polymer characterization

    When coupled with a concentration detector such as the Optilab T-rEX, the ViscoStar II can be used to derive the intrinsic viscosity of polymers. The intrinsic viscosity, in turn, can be used to derive the hydrodynamic radius and shape information about a macromolecule in solution.

    Universal calibration is a parallel technique to SEC-MALS for determining molecular weight, commonly used to characterize polymers. While universal calibration overcomes some of the problematic issues associated with column calibration by reference standards, it does not account for non-ideal column behavior caused by chemical solute-column interactions or hyperbranching. Still, if samples are known to be well-behaved, universal calibration can be a useful check with or without MALS data.

    Key benefits

    • High sensitivity, equivalent to 1 µg/mL of 30 kDa polystyrene at 0.5 mL/min or ~ 0.35 µg injected onto a standard GPC column
    • Measurement range corresponds to over 14 mg/mL of 30 kDa polystyrene
    • Temperature control from 4°C - 60°C for polymers that require a range of temperatures
    • High-resolution, touch-screen front panel displays data graphs and diagnostics, even with the host computer turned off

    Unique features

    Most viscometers only have an internal heater, and as a result, can only regulate temperatures 10°C above room temperature. The ViscoStar II is the only viscometer that can regulate temperatures at or below room temperature, as well as above - between 4°C and 60°C.

    With the ViscoStar II and the band broadening correction in ASTRA, you can correct for interdetector broadening and can display the true, constant intrinsic viscosity.

  • Viscometry-only

    The ViscoStar II may be used with any* GPC or HPLC-SEC system as long as the sample does not need to be heated above 60°C in order to flow through 0.010" (0.25 mm) i.d. tubing. Combine with an Optilab T-rEX for the concentration measurements needed in viscometry calculations.

    Would you like to use your GPC's or other 3rd party software? The ViscoStar II provides an 18-bit analog output signal for this type of operation, as does the Optilab.


    Combine the ViscoStar with a DAWN HELEOS II MALS detector for an even more versatile combination that can determine Mark-Houwink-Sakurada parameters and other measures of conformation and stability. ASTRA handles all the calculations you need for full characterization of your polymers.

    *Certain HPLC pumps or injectors generate pressure pulses that can interfere with sensitive differential viscosity measurements. This email address is being protected from spambots. You need JavaScript enabled to view it. for information on optimal GPC systems.

  • Orbit - The Orbit helps conserve mobile phase by programmatically directing the solvent to either a waste bottle or back to the solvent reservoir.

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

    WISH Injection Module - The Wyatt Injection System High-Pressure (WISH) is ideal for use when an autosampler is not available. The WISH triggers data acquisition by ASTRA upon injection.

    SysTrack - A convenient rack for holding multiple Wyatt instruments.

  • Specific Viscosity
       Sensitivity 1.8 x 10-5 †
       Range 0 - 0.8
    Differential Viscosity
       Precision 18 bits
       Linearity 0.5% of full scale
       Integration time 0.1 sec to infinity, increments of 0.1 sec
       Max. differential pressure 5 kPa (0.725 psi), protected against overpressure
       Max. differential pressure noise < 0.15 Pa (2.2·10-5 psi)
       Max. differential pressure drift < 2.5 Pa/hr (3.6·10-4 psi/hr)
       Sample shear rate 5000 Hz *
       Max. flow rate 1 – 3 mL/min (solvent dependent)
       Delay volume options 13.9, 6.1 and 2.3 mL
       Max. permissible pressure at outlet 220 kPa (31.9 psi)
       Max. permissible internal system pressure 690 kPa (100 psi), protected against overpressure
       Cell Volume 33 µL / bridge arm
       Bridge capillary i.d. 0.25 mm
       Wetted Materials 316 and 410 stainless steel, PTFE, zirconium silicate, Kalrez®
    Temperature Control
       Range 4°C – 60°C
       Stability <0.01°C
       Ambient Range 0°C – 40°C
       Inputs Autoinject, Alarm In. Analog In: 1 differential input, 16 bits resolution, range -10 V to +10 V
       Outputs Autoinject Retransmit, Alarm Out, Recycle Out, Analog Out (differential pressure and inlet pressure, 18 bit)
    On-board Computer
       Display / User Interface 162.5 mm, high-resolution, color LCD touch-screen display
       Communications Ethernet
    Dimensions 60 cm (L) x 36 cm (W) x 17 cm (H)

    Toluene at 0.5 mL/min, 25°C
    * Aqueous buffer at 1.0 mL/min

    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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