RD2: 250-280

UV Monitor for Preparative liquid chromatography and FPLC

GeneralSpecificationsOptionsFraction RouterUser Manual

Operation mode

Autonomous: all unit functions are controlled from the front panel, so no external PC is needed.

Data presentation

Two real-time graphs (one for each data channel) are plotted on a color LCD.

Light sources

  • 250nm and 280nm UV LEDs, followed by narrow bandpass diffraction filters
  • Spectral bandwidth: 9nm
  • Wavelength accuracy: ± 2nm
  • Current through UV LEDs: ≈ 10% of the maximum allowed for the corresponding UV LED. The operating current reading is available on the detector's screen.
  • Thermally compensated to minimize long-term drift
  • Typical lifetime: 15 years of non-stop operation

Flow cell*

  • A sinlge wide-range embedded flow cell is implemented, patent pending.
  • Total volume: 30μl
  • Flow rates: 0.1 to 300ml/min, no split - all eluents travel through the flow cell via the same path.
  • Maximum operating pressure: 250 psi (17 bar)
  • Wetted materials: quartz and titanium
  • Solvents compatibility: any (except HF; see manual)
  • pH stability (long term): 1-13
  • pH stability (short term): 1-14
  • Hydrodynamic resistance: low, suitable for gravity chromatographic columns

Monitoring of UV absorption at 250 and 280 nm

  • Range: 0.001 – 100* AU (Absorption Units)
  • Resolution: 0.0001 AU
  • Baseline noise: < 0.0001 AU
  • Drift: 3.0 x 10-4 AU/hr at constant temperature
  • Auto-zero: the detector may be zeroed at any time

Data storage

Data is saved automatically to the internal non-volatile memory. The memory can hold a maximum of 35,000 data points.

Acquisition rates (non-stop run times)

  • 5Hz (1 hour 49 min)
  • 2Hz (5 hours 27 min)
  • 1Hz (9 hours 5 min)
  • 0.5Hz (18 hours 11 min)
  • 0.2Hz (45 hours 28 min)
  • 0.1Hz (90 hours 56 min)

Data Transfer

By user's command to USB drive. No data acquisition occurs during data transfer.

Communication Interface

  • One digital fraction count input from a fraction collector; detector can react to intermittent mechanical contact closure and TTL level signal.
  • 2 independent analog outputs in 0-1V range (see manual for transfer functions), corresponding to (a) UV 250 nm, and (b) UV 280 nm. The output (a) can be reassigned by a user to provide data from (b) channel and used to provide the respective analog signal for contemporary fraction collectors.
  • All input and output channels are galvanically isolated from mains ground and detector's internal circuitry ground for safety and noise resistance.


  • Dimensions: 5.7” diagonally
  • Resolution: QVGA 320x240
  • Back-light: white LED
  • Protection: hermetically covered with 2 mm glass – the assembly is solvent resistant.

Case material

Anodized titanium, covered with 1 micrometer Teflon – complete resistance to any solvent spills.


7.5” x 5.25” x 2.25” (190 x 133 x 57 mm)


3 lb (<1.4 kg)

Power requirements

  • Embedded internal (USA, Asia, and most other regions) or included external (Canada, Europe) power supply
  • Frequency: 50-60Hz
  • Voltage: 90-240V
  • Current rating: 0.1A for 90-120V, or 0.06A for 220-240V; 10W max power draw

*The data is simultaneously collected for optical path-lengths 0.001 to 1 mm, and presented to user “as if” the acquisitions occurred using a 1 mm optical path-length. Unlike other UV monitors, the chromatogram data collected by RD2 detector does not plateau when concentrations of UV-absorbing compounds are high, allowing the user to see true analyte peaks as they leave the column.

Superior performance that outclasses all comparable instruments

The comparison chart of commercially available UV detectors and monitors for liquid chromatography

How to Choose a UV Detector for Chromatography Applications