Waters/Wyatt Optilab On-line Differential Refractometer

Independent of Chromaphores

Independent of chromaphores or fluorophores, differential Refractive Index (dRI) detectors serve as accurate and versatile concentration detectors in all types of solvents. dRI is part of standard instrumentation for a variety of macromolecular characterization techniques including standard chromatography, SEC-MALS, FFF-MALS and CG-MALS.

Unique dRI Detector

The Optilab is a unique dRI detector for standard HPLC/GPC with 256 times the detection power and 50 times the dynamic range of every other RI detector for chromatography in existence today, making it a valuable addition to any MALS setup.

Product Description

Using a combination of cutting-edge semiconductor photodiode technology and proprietary computer algorithms, the Optilab achieves an unprecedented combination of sensitivity and range. These features mean that it addresses both standard chromatographic applications and some challenges unique to light scattering measurements such as high concentrations, determination of sample refractive increments (dn/dc) and solvent refractive index.

Key Benefits

• Extraordinary dRI measurement range, -0.0047 to +0.0047 RIU (comparable to 25 mg/mL protein in PBS)
• Highly sensitive, ±7.5 x 10 -10  RIU across the entire measurement range
• Measures solvent absolute refractive index, required for MALS calculations
• Measures at the same wavelength as the MALS detector, for maximum accuracy in MALS calculations
• Band broadening < 20 µL preserves SEC resolution
• Temperature range 4 °C to 65 °C for proteins and 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

Unparalleled Features

Even though the Optilab offers a dRI measurement range orders of magnitude beyond that of other dRI detectors, unlike other detectors there are no range or gain settings in the Optilab. The full range of instrument detection is always present, and the full sensitivity exists over the entire range.

The Optilab can also do something no other on-line refractive index detector can: it can measure the absolute refractive index of a solution. In addition, it can measure the dn/dc of a solvent at the same wavelength of light as the light scattering instrument. And just to make sure it can't be matched, you can replace the light source in the Optilab for other wavelengths (e.g., 690, 633, 488, etc.) in just minutes!

The Optilab can go below ambient temperatures as easily as above ambient. No hassle temperature control can be programmed from 4 °C to 65 °C. Compatible with all HPLC systems.

Specifications

Measurement Capabilities – Differential Refractive Index

Standard Optilab Configuration

• Measurement Range: –0.0047 to +0.0047 RIU
• Peak-to-Peak Noise: ±7.5 × 10⁻¹⁰ RIU
  (Measured per ASTM-E1303-95 at 25 °C)

High Concentration (HC) Option

• Measurement Range: –0.0026 to +0.034 RIU
• Peak-to-Peak Noise: ±1.5 × 10⁻⁹ RIU
  (Optimized for higher concentration samples)
• Response Time: User-selectable from 0.1 to 5 seconds
• Absolute Refractive Index Measurement Range: 1.2 to 1.8 RIU
• Absolute RI Sensitivity: ±0.002 RIU

Fluidics and Flow Properties

• Band Broadening: <12 µL
• Fill Volume (Inlet Tubing + Flow Cell): 51.4 µL
• Outlet Tubing Volume (0.030" ID): 370 µL

Pressure Ratings

• Inlet Back Pressure (0.5 mL/min H₂O @ 20 °C): <22 psi (1.5 bar)
• Max Outlet Back Pressure: 30 psi (2 bar)

Temperature Control

• Sample Temperature Control Range: 4 °C to 65 °C
• Regulation Stability: ±0.005 °C

Light Source Options

• Standard: 660 nm
• HC Model (Optional): 488 nm, 785 nm, or 940 nm

Safety Features

• Built-in vapor and liquid leak sensors for enhanced lab safety

Electronics and Connectivity

• Digital Output: 22+ bit resolution @ 10 Hz
• Analog Output: ±10 V or ±1 V, 18-bit resolution
• Computer Interface: Ethernet

Auxiliary I/O Ports

• Inputs:
  • Analog In (16-bit, ±10 V A/D)
  • Zero dRI
  • Purge
  • Recycle In
  • Autoinject In
  • Alarm In
• Outputs:
  • Autoinject Retransmit
  • Alarm Out
  • Recycle Out (controls Orbit™ valve switching)

User Interface

• Front Panel Display:
  7” (178 mm) high-resolution multi-touch screen for viewing signals, diagnostics, and adjusting instrument settings

Instrument Dimensions

• Size: 58 cm (L) × 36 cm (W) × 18 cm (H)

Other Refractive Index Detectors

• microOptilab™ - The first RI detector specifically designed for use with all UHPLC systems.