Molecular Devices SpectraMax Paradigm User Manual page 181

Stokes Shift
The Stokes shift is the difference between the wavelengths of the excitation and emission
maxima, or peaks.
See Emission Spectrum Scan on page 176
T
Time-Resolved Fluorescence (TRF)
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.
See Time-Resolved Fluorescence Read Mode on page
%Transmittance
%Transmittance is the ratio of transmitted light to the incident light for absorbance reads.
T = I/I
%T = 100T
where I is the intensity of light after it passes through the sample and I
before it enters the sample.
5014038 E
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and Excitation Spectrum Scan on page
38.
Glossary
176.
is incident light
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181