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Just
released!
The brand-new, top-modern
successor software for Spekwin32
Spectragryph
1.0
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Fluorescence/
EEM menu
1.
Menu Item [Emission Sensitivity Correction]
- For correction
of the wavelength dependent sensitivity of detectors of fluorescence
spectrometers. Yields "true spectra".
- Load the
correction curve with the button [Load correction Curve] (*.fak file,
has to consist of XY pairs with sensitivity against wavelength). Select
the spectrum to be corrected in the middle drop down list. The corrected
spectrum will be added to the list of spectra, the legend title will
be appended with "corrected".
- Options:
- [delete
original ] deletes the original spectrum.
- [correct
all] corrects all loaded spectra and deletes the original spectra.
2.
Menu Item [Excitation
Wavelength Assignment]
- To prepare
a set of fluorescence spectra as two-dimensional spectrum or EEM (excitation
emission matrix), each spectrum needs its excitation wavelength assigned.
- This can
be entered manually for each spectrum in the menu item [General] (4.1),
or automated for a complete set of spectra from this menu item.
- Just enter
the excitation wavelength of the first spectrum and the excitation step
width.
- In case
your EEM set comprises only a part of the loaded spectra, select the
first and last spectrum of the set in the two drop down lists.
- For naming
the spectras' legend texts with the excitation wavelength, activate
the "replace spectrum names
" checkbox.
3.
Menu Item [Correction
of Excitation Intensity]
- For correcting
the wavelength dependent excitation intensity (lamp spectrum) of fluorescence
spectrometers for a series of fluorescence spectra with known excitation
wavelength.
- Load the
lamp correction curve with the button [Load Lamp Spectrum]. Select the
range of spectra to be corrected with the two drop down lists. The corrected
spectra will replace the original spectra, their legend titles will
be appended with "Excitation intensity corrected".
- Hint:
The wavelength can be entered manually for each spectrum in the menu
item [General].
4.
Menu Item [Remove Rayleigh/ Raman Scatter]
- Often enough,
and especially for samples with low intensity fluorescence, EEMs are
distorted by scattering peaks. These come from first and second order
Rayleigh scattering as well as Raman scattering and can't be fully suppressed
even by choosing optimal geometries of sample container and optical
pathways. For being further used in chemometrics analysis, scattering
has to be removed. Traditionally this has been done by setting the scattering
regions to zero, but there are much better ways to reduce the influence
of straylight.
- This menu
item allows to remove all scattering from a whole EEM set at once with
this options:
- [treat
all spectra] applies the treatment to all loaded spectra at once.
- "
[remove original(s)] removes the original spectrum/ spectra from
display.
- With
[replace by] you can replace the values of the scattering region
by
-
zeroes, this is the traditional & most ugly way of doing
it
- o
a straight line, which might be better in some cases
-
an interpolated curve, which is most useful, because it give
the least distortion. The interpolated values have the same
noise level as their surrounding
- set
the excitation bandwith of your spectrometer, this defines the width
of the replaced values area
- [remove
Rayleigh peaks (1st order)] removes the scattering intensity around
your excitation wavelengths (visible because your sample does it)
- [remove
Rayleigh peaks (2nd order)] removes the scattering intensity around
twice your excitation wavelengths (visible because your emission
monochromator leaks the 1st order scattered light into it's 2nd
order wavelength range)
- [remove
Raman peaks (1st order)] removes the scattering intensity around
the Raman-shifted excitation wavelengths. The wavelength difference
is solvent dependent, some solvents can be selected from the drop
down list. You can include other solvents by editing the file "RamanBands.csv"
from the Spekwin32 program folder.
5.
Menu Item [Subtract Blank EEM dataset]
- It might
be useful to subtract the fluorescent properties of a "Blank"
sample from the EEM you want to analyze. This can be successfully used
to remove background fluorescence and also scattering peaks.
- In the
upper part you can see the dimensions of your current EEM set. Load
the Blank dataset to be subtracted with [Load Blank dataset
].
This naturally will only work if the dimensions of both datasets are
identical.
- Optionally,
"blank subtracted" can be appended to the legend texts.
6.
Menu Item [Show 2D Spectrum (EEM)]
- Two-dimensional
display of a series of fluorescence or excitation spectra. EEM means:
Excitation Emission Matrix. The spectra should
be connected to a wavelength and be corrected for excitation intensity
before (see above). Example:2d_beispiel.zip
(315KB)
- The mouse
position is shown in the lower left corner as excitation, emission and
intensity values. On the right there are some options for display. By
default, excitation is oriented horizontally, emission goes vertically.
- This orientation
can be exchanged by using the [switch x <=> y axes] option. The
EEM plot can be copied to clipboard with [Copy => Clipboard].
- You cannot
print or save the graph at the moment, there are no axes.
7. Menu
Item [Calculate Excitation
Spectra]
- For calculating
a series of excitation spectra from a series of fluorescence spectra.
The spectra have to be connected to a wavelength and should be corrected
for excitation intensity before(see above).
- Enter the
range and stepwidth of detection wavelengths for the excitation spectra.
Fluorescence spectra will be removed if [Remove Fluorescence spectra]
is checked.
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