Waters/Wyatt microViscoStar viscometer

Highly Sensitive

A highly sensitive, on-line differential viscometer used with SEC-MALS-IV to determine the size and conformation of polymers, proteins and peptides separated by UHPLC.

Multiple Novel Technologies

The microViscoStar™ incorporates multiple novel technologies to provide the highest sensitivity, stability and solvent compatibility of any available viscometer for UHPLC. Its ease-of-use and serviceability make it the perfect companion for Wyatt's microDAWN™ light scattering and microOptilab™ refractive index detectors for UHPLC.

Another path to polymer and protein characterization: SEC-MALS-IV

When coupled with size-exclusion chromatography and a concentration detector such as the Optilab™ , the microViscoStar derives the intrinsic viscosity (IV) of polymers. An inherently valuable physico-chemical property in itself, IV is best utilized together with molar mass information from multi-angle light scattering (SEC-MALS-IV) to derive the hydrodynamic radius, conformation, and branching ratio of a macromolecule in solution.

Waters microViscoStar: Patented pulse compensation technology in the microViscoStar eliminates pump fluctuations. At the hardware level, the bridge is impedance-matched for dynamic balance, greatly reducing the effect of pump pulses. An additional layer of software filtering eliminates residual pump pulses.

Key benefits of the ViscoStar

• High sensitivity, equivalent to 5 ng of 100 kDa polystyrene in THF at 1.0 mL/min injected onto a standard GPC column
• High dynamic range of over 135,000:1. The full measurement range corresponds to over 13 mg/mL of 100 kDa polystyrene in THF
• Extended solvent compatibility with all-316 stainless steel transducers
• Temperature range from 4 °C to 70 °C for polymers or proteins that require a range of temperatures
• Minimal band broadening thanks to fast pressure transducers
• Pump pulse suppression to below 4 Pa (hardware alone) or 1 Pa (hardware + software) without loss of chromatographic resolution
• Automated capillary bridge tuning with no moving parts, to guarantee a perfectly balanced bridge, every run
• Enhanced thermal stability with drift of <1.25 Pa/hour

SEC-IV without MALS?

Yes, as much as we love MALS for optimal polymer analysis, it's true that there are occasions when it just won't fit the bill.

Universal calibration is a parallel technique to SEC-MALS for determining molecular weight, commonly used to characterize linear polymers. While universal calibration overcomes some of the problematic issues associated with column calibration by reference molecules, it does not account for non-ideal column behavior caused by chemical solute-column interactions or hyperbranching.

Universal calibration is particularly-well suited to replace MALS for:

• Strongly fluorescent polymers
• Weakly-scattering polymer/solvent systems with very low dn/dc values

The Mark-Houwink-Sakurada relationship makes use of empirical relationships between intrinsic viscosity and molar mass, specific to each polymer and solvent, to estimate molar mass from SEC-IV measurements. Of course, the best way to determine MHS coefficients is to measure them using SEC-MALS-IV and ASTRA™

Specifications

Measurement Capabilities – Differential Viscosity

• Sensitivity:
  Detects as little as 5 ng of 100 kDa polystyrene in THF at 1 mL/min under typical UHPLC-SEC conditions.
• Differential Pressure Performance:
  • Noise: < 0.05 Pa
  • Range: Up to 6.9 kPa, with overpressure protection
  • Drift: < 1.25 Pa/hr
  • Linearity: Within 0.5% of full scale
  • Dynamic Range: 135,000:1
• Capillary Bridge Autobalance:
  Thermal, leak-free mechanism ensures stable baseline performance.
• Sample Shear Rate:
  Up to 15,000 Hz with water at 1 mL/min for high-resolution viscosity profiling.

Fluidics and Compatibility

• Maximum Flow Rate:
  Aqueous and THF: up to 1 mL/min
  (Note: Using an inline UV detector may reduce allowable flow rate.)
• Delay Volume:
  5.4 mL
• Maximum Inlet-to-Outlet Pressure:
  3000 kPa (435 psi)
• Wetted Materials:
  316 stainless steel, PTFE, zirconium silicate, Kalrez®, Inconel, 26-1 stainless steel, and nickel

Note: Due to the location of wetted components, this instrument is primarily recommended for use with organic solvents. High-ionic-strength buffers may cause corrosion.

Temperature Control

• Operating Range:
  4 °C to 70 °C
• Stability:
  Maintains temperature within < 0.005 °C
• Ambient Conditions:
  0 °C to 40 °C; 20% to 70% relative humidity

Electronics and Connectivity

• Digital Output:
  20-bit resolution at 10 Hz
• Auxiliary I/O:
  • Inputs: Autoinject contact closure, Alarm In, and 2 analog inputs (16-bit, ±10 V)
  • Outputs: Autoinject retransmit, Alarm Out, Recycle Out
• Communication Interface:
  Ethernet

User Interface

• Front Panel Display:
  7” (178 mm) high-resolution, capacitive multi-touch screen for real-time monitoring, configuration, and diagnostics

Instrument Dimensions

• Size: 60 cm (L) × 36 cm (W) × 17 cm (H)

Other Viscometers

• ViscoStar™ - A highly sensitive, on-line differential viscometer used in conjunction with SEC-MALS to determine the size and conformation of all types of biopolymers, synthetic polymers and even proteins and peptides.
• The ViscoStar incorporates multiple novel technologies to provide the highest sensitivity, stability and solvent compatibility of any available viscometer for GPC. Its ease-of-use and serviceability make it the perfect companion for Wyatt's DAWN® light scattering and Optilab® refractive index detectors. Temperature-controlled from 4 °C to 70 °C .