Horiba Scientific FluoroMax-4 Operation Manual page 223

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FluoroMax -4 & FluoroMax -4P with USB rev. D (30 Jul 2012)
Monochromator
Multifile
Multigroup
Neutral-density filter
Optical density
Optical-density effects
(Inner-filter effect)
Phosphorescence
Photobleaching
Photoelectron
Photon-counting detec-
The component in a spectrofluorometer that is scanned to provide the
excitation and emission spectra. Monochromators are chosen for stray-
light rejection, resolution, and throughput.
The three-dimensional acquisition datafiles collected by the software
using matrix scans or temperature scans, stored as an array of datafiles.
A multifile is still stored with an .SPC extension. Multifiles may be
used in their entirety in FluorEssence™ as 3D files, or they may be
split up into individual two-dimensional spectra using multifile utili-
ties.
This special software allows a time-based scan to be acquired across
more than one excitation/emission pair. Up to 16 different wavelength
pairs may be entered for a multigroup scan. The spectrofluorometers
will cycle through each pair, integrating for the specified time, before
moving on to the next point. Use Multigroup software for measuring
ratiometric probes (such as Fura-2 or BCECF).
An optical element that absorbs a significant fraction of the incident
light. These filters usually are characterized by their optical density, on
a logarithmic scale. For example, a filter with OD = 1 transmits 10% of
the incident light. Ideally, these filters absorb all wavelengths equally.
See also Absorbance.
A synonym of absorbance. See Absorbance.
Fluorescence intensities are proportional to the concentration over a
limited range of optical densities. High optical densities can distort the
emission spectra as well as the apparent intensities. See also Inner-
filter effect.
The emission of light or other electromagnetic radiation during the
transition of electrons from the triplet state to the ground state. Phos-
phorescence is generally red-shifted relative to fluorescence and occurs
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within ~10 to ~1 second. To enhance phosphorescence, samples often
are frozen at liquid-nitrogen temperature (77 K).
The reduction in fluorescence from a photosensitive sample overly ex-
posed to excitation light. Not all samples photobleach, but if so, take
care to keep the sample out of room light, and to use the excitation
shutter and its photobleach modes on the spectrofluorometer to protect
the sample from excessive exposure.
An electron released through the interaction of a photon with the active
element of a detector. The photoelectron may be released either from a
junction to the conduction band of a solid-state detector, or from the
photocathode to the vacuum in a PMT. A photoelectron is indistin-
guishable from other electrons in any electrical circuit.
A method of detection used primarily with photomultiplier tubes, in
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Glossary