Geoscience Reference
In-Depth Information
Table 5.3.
Luminescence dependence
Parameters
Φ
, Quantum yield
I
, Fluorescence Intensity
P
, fluorescence polarization
r
, fluorescence anisotropy
Dependence on one parameter
I(
λ
), spectra: excitation, emission, synchronous
I
(c), concentration or titration
I
(
T
), temperature
r
(
λ
), spectrally resolved anisotropy
I
(t), time-resolved
Dependence on two parameters
I
(
λ
,t), time-resolved emission spectra
I
(
λ
exc
,
λ
em
), excitation-emission spectral maps (EEM)
I
(
λ
,
T
), temperature resolved spectra
R
(
λ
,
t
), time and spectrally resolved anisotropy
Emission
Monochromator
Excitation
Charge-
Coupled
Device
Monochromator
450W
Xenon
Lamp
Sample
Figure 5.6. Basic fluorimeter arrangement.
bearings on the results, not only from day to day, but also instrument-to-instrument and
laboratory-to-laboratory. It is these drawbacks, such as intensity, wavelength, polarization
and time-resolved behaviors, of all fluorescence- based detection methods and their proper
removal that make accurate measurement of the absolute fluorescence intensities extremely
difficult. At the same time there are still relatively few fluorescence standards readily avail-
able that can be used to demonstrate instrument performance validation through rigorous
characterization of the instrument. The basic measurements of excitation and emission
spectral measurements, once mastered, are the foundation of all other measurements such
as those referred to in
Table 5.4
.
