catecholamine fluorescence and pH

[Wolfgang Schechinger]

<crossposted to bionet.molbio.methds-reagnts>

Beat, I think you're right. 

Deprotonating the phenols should shift the optical properties 
drastically. Normally this kind of phenomenon is utilized in stuff 
like litmus to indicate pH. 
Might there be some useful application I'm not aware of?


To Rikke: 

You could try to derivatize (sp?) the catecholamines to soemthing 
fluorescent. I'm not sure about the substance, but I think it's e.g. 
sangers reagent (fluoro-2,4-dinitrophenol) that you may use. At 
least, it is a method used in clinical chemistry (separation of 
catecholamines by HPLC, derivatization and subsequent detection). If 
there is nobody around here who knows it, call the next university 
clinic. They should know.

Wolfgang


> Sorry, I can't answer your questions. I'm just curious, have you
> checked whether the fluorescence returns (immediately) upon
> neutralization? The would suggest a simple de-protonation.
> 
> Cheers,
> 
>  Beat
> 
> >Hello - I am not quite sure, this is the right newsgroup to ask
> >this question in - but I'm more or less desperate.....
> >
> >I would like to know how the fluorescence spectra of  the
> >catecholamines adrenaline/ephinephrine and
> >noradrenaline/norepinephrine) change with pH .
> >
> >The compounds seem to decompose in even slightly basic media (e.g.
> >pH=8.5) - the fluorescence vanishes. Is this due to oxidation of
> >phenoles??? - or is it another cause?  Will you under any
> >circumstances be able to measure catecholamine fluorescence in
> >basic solution?
> >
> >Furthermore, does anybody know where the catecholamine's chemical
> >and fluorescence properties might be described in detail?
> >
> >Thanks in advance
> >Rikke
> >
> >
> >---
> 
> 
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Dr. Wolfgang Schechinger, Dept. of Pathobiochemistry
University of Tuebingen, Germany
email: wolfgang.schechinger at med.uni-tuebingen.de 
wwWait: http://www.medizin.uni-tuebingen.de/~wgschech/start.htm
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