PerkinElmer EnVision, Instrument Manual

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Functional description
17
TR-fluorescence mode
In time-resolved fluorescence measurements the sample are excited by the
flash lamp and the generated fluorescence is read by the photomultiplier
tube in single photon counting mode. The basic measurement needs only
one flash, but more flashes (i.e. 100) ensure higher accuracy. The integrated
photon counts from the photomultiplier and the integrated analog signal
from the reference photodiode are always read after every flash. For one
measurement (one or more flashes) these readings are summed (not
averaged). The reference signal is then compared with the original reference
value obtained with the same label and the results are corrected so that they
each come from the same excitation energy.
Most TRF-measurements are done in epi-mode i.e. excitation from above
and reading from above or excitation from below and reading from below,
or in through mode. The general mirror module (2100-4010) with 50/50
beamsplitter mirror can be used for all labels independent of the excitation
and emission wavelengths. For dual detection the dual general mirror
module (2100-4050) is needed. For better detection limits the UV mirror
module (2100-4170) should be used. The dichroic mirror of this mirror
module is optimized for excitation of different chelates. The dual mirror
module (2100-4160), for instance for dual label DELFIA (Eu/Sm), is
equipped with a secondary dichroic mirror with a cut-off wavelength of 630
nm. With this mirror module different epi-measurements can be performed.
Figure 13. Excitation from above/Reading from above
Figure 14. Excitation from above/Dual reading from above