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DELFIA Instrument Options and Settings

DELFIA assays require a plate reader that is capable of TRF (time-resolved fluorescence) detection. This is a time-resolved fluorescence intensity assay. We recommend using a PerkinElmer VICTOR™ or EnVision® Multilabel Plate Reader (view our instrument product pages). If you are using a plate reader manufactured by another company, you can use our Europium standard solution (catalog number B119-100) and perform a serial dilution in DELFIA Enhancement solution to determine the sensitivity of your instrument. We also offer Samarium standard solution (catalog number B115-100) and Terbium standard solution (catalog number C558-100) if you are interested in multiplexing.

  • Fluorometers (filter fluorometer) vs. spectrofluorometers/monochromators

    We recommend a time-resolved filter-based fluorometer for DELFIA Europium assays. Very sensitive time-resolved spectrofluorometers may be suitable for certain assays. Most plate readers are capable of TRF-type assays - a flash lamp is needed for TRF analysis, which is an option on most plate readers. You could also use laser excitation on an appropriate EnVision instrument.

    • A TRF filter fluorometer plate reader utilizes bandwidth filters in front of the fiber optic for excitation and in front of the detector for emission wavelength choice. The grating-type spectrofluorometers are generally less sensitive than filter fluorometers, and loss in sensitivity can cause issues in highly sensitive assays such as TRF.
    • A TRF-capable spectrofluorometer utilizes a monochromator (usually an excitation and emission grating) to discriminate wavelength positions of study for fluorescence excitation and emission. Spectrofluorometers can be up to 1000-fold less sensitive than filter fluorometers, though spectrofluorometers may work in some DELFIA applications.
    • The new double-monochromator instruments claim to have almost similar sensitivity as the ‘original’ filter readers. These may be suitable for most DELFIA assays.
    • For cell-based assays, top illumination is recommended, as some clear-bottom plates may absorb excitation at 340 nm. Top illumination is naturally required with white and black plates.


  • DELFIA Instrument Settings when using DELFIA Europium

    We recommend generic default instrument settings for all DELFIA assays. We always recommend you check with the manufacturer of your particular instrument to see if they have additional recommendations for DELFIA assays.

    • Settings for a filter fluorometer:
      • Excitation: 320 or 340 nm
      • Emission: 615 nm
      • Delay: 400 µsec
      • Window: 400 µsec
      • Cycle: 1000 µsec
      • Flash energy: high
    • Settings for a spectrofluorometer/monochromator:
      • Excitation: 320 or 340 nm
      • Emission: 615 nm
      • Delay: 100 µsec
      • Integration time: 1000 µsec (when using flashlamp 500 kHz or slower)
      • Highest sensitivity, gain, Z-optimal
    • Settings for an EnSpire™ TRF option Multi-Label Plate Reader
      • Excitation filter: UV (TRF340) dug11 + wg320 filter
      • Emission: 615 nm
      • Delay time: 200 µs
      • Window: 500 µs
  • DELFIA Instrument Settings when using DELFIA Terbium

    • Settings for a filter fluorometer:
      • Excitation: 340 nm
      • Emission: 545 nm
      • Delay: 500 µsec
      • Window: 1400 µsec
      • Cycle: 2000 µsec
      • Flash energy: high

If you are working with Terbium and/or Samarium, please view the measurement information on our DELFIA multiplexing page.