horiba FluoroMax-3, Руководство по эксплуатации

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FluoroMax-3 v. 3.1 (6 Mar 2006) Glossary
13-1
13: Glossary
Absorption
The electronic transition from the ground state to the excited singlet
state, by absorption of a photon of a particular energy. This process
typically occurs in ~10
–15
s.
Absorbance
The extent of light absorption by a substance, –log T , where T is the
transmittance of the sample. Absorbance is also synonymous with
optical density, OD. Absorbance is defined as
A =
ε
cl = OD = – log T
where
ε
is the extinction coefficient ( M
–1
cm
–1
), C is the sample con-
centration ( M ), and l is the path length (cm).
Acquisition modes (R, S
channels)
The logical input channels used on the spectrofluorometer to input
collected signal from the detectors present on the system. The detec-
tors are assigned as: the reference detector connected to channel
R ,
and the emission connected to channel S . These logical channel
names are used in the collection of data in most FluorEssence™ ap-
plications. The user may create algebraic expressions on these input
channels when defining experiments in FluorEssence (e.g.,
S/R ).
Anisotropy (<
r
>)
A measurement of the fluorescence polarization of a samples, defined
as the linear-polarizer’s component’s intensity divided by the total
light intensity. The measurement of anisotropy can provide insight
into molecular size and shape, as well as the environment that sur-
rounds it.
Autopolarizers
An automated device to hold and precisely rotate a set of polarizers
to acquire anisotropy (or polarization) measurements. FluoroMax
®
-3
systems with autopolarizers contain two automated polarizer mounts,
one for the excitation polarizer and one for the emission polarizer.
Both are located between the sample compartment and their respec-
tive monochromators. Their calibration is maintained by optical sen-
sors that are offset in the software. Autopolarizers on the Fluoro-
Max
®
-3 may be inserted into and out of the light path in FluorEs-
sence™, in the
Experiment Setup
window, under the
Accessories
icon. (Automated realignment of the polarizers also may be per-
formed here.)
Bandpass
The range of wavelengths of light passing through the excitation and
emission spectrometers, usually expressed in nanometers (nm). This
value is dependent on the size of all slits in the monochromator, as
well as the dispersion of the monochromator. For spectrofluorome-
ters, both slits on the monochromator should be set equal to properly
set the bandpass, if not done automatically through the software.
When adjusting the bandpass for samples, the wider the bandpass, the
higher the signal intensity, with a trade-off in lower resolution.