In Synchronous spectrum, both Exc and Fl monochromators are scanned simultaneously. MY questions are;
1) How to determine delta wavelength
2) if delta wavelength is 20nm, does it mean the data point at 400nm corresponds to excitation at 380nm? and point at 480nm corresponds to excitation at 460nm.
3) which synchronous technique ( wavelength or energy) is more preferred and informative.
1 - it really depends on what you want to see (if you chose the wavelength offset to be equal to the Stokes shift of a particular fluorophore in your sample, you will observe much more pronounced maxima of the fluorescence of this fluorophore in comparison with others present in your sample)
2 - if you chose offset of 20 nm and excitation at 380 nm the detection will be at 400 nm
3 - it really depends on what you want to see, but I can't give you any advise here, since I have used only the wavelength method.
It depends on what you are looking for. The Excitation Emission Matrix is generally more informative than the Synchronous scan...
The issue is it takes a long time to perform on a system with 2 monochromators so a synchronous scan can sometimes be used in rare cases.
Attached is a schematic of an EEM with an excitation spectrum, emission spectrum and a synchronous scan (all plotted using wavelength).
Attached also is an EEM of water with and without the Rayleigh lines masked. Note the Raman shift in wavenumbers is constant for water... The gap in energy difference may be useful if one wants to look exclusively at the Raman line...
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