[RASMB] 200 nm buffer salts

[Holger Strauss]

Hi Marc,

there will be a problem with the fluoride anion when the pH of the
solution will be less than pH 7 or so (I don't have the pKa of HF at
hand), since the small amounts of HF present then will damage the quarz
windows (and since the HF is removed from the initial protonation
equilibrium, that process won't stop) 
and sapphire can't be used below 240 nm if I remember correctly.
It should be possible to change the NaF for K2SO4, but other factors
will also be important, like CO2 and O2 content of your solutions, to get 
good S/N; there is a reference desribing some methodological details and
precautions: 

Scopes-RK, Measurement of Protein by Spectrophotometry  at 205 nm,
Analytical Biochemistry 59:277 (1974) 

and the references therein which might be of some use in your case.

Cheers, Holger

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Holger Strauss 

Forschungsinstitut fuer Molekulare Pharmakologie (FMP)
Robert-Roessle Strasse 10

13125 Berlin/Germany

Tel: +49 (0)30 94793 - 223 (office)
                     - 316 (lab)

Fax: +49 (0)30 94793 - 169 


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Science is spectrum analysis; art is photosynthesis.

                                                    Karl Kraus