Horiba Scientific FluoroMax-4 Operation Manual page 221

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FluoroMax -4 & FluoroMax -4P with USB rev. D (30 Jul 2012)
Flash lamp
Fluorescence
Fluorescence lifetime
(τ)
Fluorophore (fluores-
cent probe)
Front-face detection
Grating
Ground state (S )
0
High-pass filter
Increment
Inner-filter effect
Integration time
A lamp that provides pulsed-light output to excite a sample. Can be
either "free running" or "gated."
The emission of light during the transition of electrons from the excited
singlet state to the ground state from molecules originally excited by
the absorption of light. Fluorescence typically occurs within ~10
conds.
The average length of time that a molecule remains in the excited state
before returning to the ground state.
A molecule or compound that has a known fluorescence response.
These probes have various sensitive areas depending on the peak exci-
tation and emission wavelengths and their fluorescence lifetimes.
Fluorophores are used to provide information on concentration, size,
shape, and binding, in a particular medium. Good fluorophores are sta-
ble over wide pH and temperature ranges.
A mode of detection in which fluorescence is collected off the front
surface of the sample. Front-face detection usually is selected for sam-
ples such as powders, thin films, pellets, cells on a cover-slip, and sol-
ids.
Optical element in the monochromator, consisting of finely scribed
grooves that disperse white light into a spectrum.
The lowest energy level in a molecule. For fluorescence to occur, a
molecule absorbs a photon of light, thereby exciting it to the S
A fluorescence emission occurs during a transition from an excited
state S to the ground state S
1
Optical component that passes light of a higher wavelength.
The spacing between adjacent measurement points in an acquisition.
Typically, increments take the form of wavelength (nm) or time (s or
ms).
The scattering of the excitation or emission beam from a concentrated
sample by the individual molecules in the sample. This reduces the ap-
parent signal intensity from the sample creating an artifact in the data.
For this reason, we recommend using concentrations of <0.05 OD in a
1-cm-pathlength cell. Samples measured in higher concentrations
should be measured in a reduced-path-length cell, or in front-face
mode.
The amount of time that each data point is collected from the detec-
tor(s), specified in either seconds or milliseconds. Longer integration
times can help improve the signal-to-noise ratio for a measurement,
while shorter integration times reduce the amount of time required for
a scan.
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0
13-5
Glossary
–9
se-
level.
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