Molecular Devices SpectraMax Paradigm User Manual page 99

About Time-Resolved Fluorescence
Time-resolved fluorescence (TRF) is a measurement technique that depends on three
characteristics that lead to better discrimination between the specific signal, proportional to
the quantity of label, and the unspecific fluorescence resulting from background and
compound interference:
Pulsed excitation light sources
Time-gated electronics faster than the fluorescence lifetime
Labels with prolonged fluorescence lifetime
The time-gating electronics introduce a delay between the cut off of each light pulse and the
start of signal collection. During the delay, the unspecific fluorescence (caused by test
compounds, assay reagents, and the microplate) vanishes while only a small portion of the
specific fluorescence from the label is sacrificed. Enough of the specific signal remains during
the decay period with the added benefit of reduced background.
The Tunable Wavelength (TUNE) Detection Cartridge uses an ultraviolet LED that emits in the
range between 350 nm and 380 nm for excitation of europium chelates, and comes equipped
with emission filters for europium. This enables single-label europium assays to be run. See
Measurement Specifications on page
Note: Europium cryptate and terbium require excitation wavelengths below 330 nm
and cannot be measured with this detection cartridge.
For more information about time-resolved fluorescence, see
Read Mode on page
About Luminescence
Luminescence is the emission of light by processes that derive energy from essentially non-
thermal changes, the motion of subatomic particles, or the excitation of an atomic system by
radiation. Luminescence detection relies on the production of light from a chemical reaction
in a sample.
The Tunable Wavelength (TUNE) Detection Cartridge contains the components for measuring
the light intensity from luminescence. Since the light is emitted as a result of a chemical
reaction, no excitation light and no excitation filters are required to measure luminescence.
The luminescence can be measured with no emission filters, or an emission wavelength
selected from within the specified range. See
Note: This detection cartridge is not suitable for measurement of flash luminescence
reactions, which require injectors.
For more information about luminescence, see
5014038 E
100.
38.
Chapter 5: Available Detection Cartridges
Time-Resolved Fluorescence
Measurement Specifications on page
Luminescence Read Mode on page
100.
33.
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