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Strange fluorescence spectra recorded

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Angelo.530nm:
Hello everybody,

This is the first time i'm posting on a forum, so sorry if i'm clumsy or if i forgot some details.

I'm using as spectrofluorometer the FS5 from Edimburg instruments. And since 1 month,i observed strange spectra :

There is an emission (which changes according to the solvent) between 350 nm and 390 nm.

This signal depends on the excitation wavelength: if i use lower excitation wavelength (like under 320 nm) i observe a stronger emission. But usually after 380nm the signal decreases.

Also when i measure compounds with strong PLQY i do not have problem.

I always use UV grade solvent or at least fresh distilled solvent ( toluene, THF, DCM, DMSO...), i tried to wash my cuvette with strong acid ( royal water) but i still observe it. I did a scan without solvent and i measured nothing so i guess the issue is not the cuvette.

Does anybody have an idea or had already face this type of issue ?

Many thanks by advance for your answer, and of course if you need more details i'll answer !

(i tried to insert a graph to show you the type of spectra i observed but when i cliked to insert image only "[img]/[img]" appears  ??? :'(   )

Have a nice day,

Angelo

Corribus:
Probably would need to see some sample spectra to diagnose. Just so I'm clear, you see fluorescent from pure solvent with nothing else in it? Are you aware that some solvents show fluorescence in the UV region, esp those featuring aryl groups (benzene, toluene, etc.)? You can acquire excitation spectra, which can help diagnose mystery PL.

billnotgatez:
@Angelo.530nm


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(i tried to insert a graph to show you the type of spectra i observed but when i cliked to insert image only "[img]/[img]" appears  ??? :'(   )
...

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