Phil Calvert wrote:
>> I am planning to label some amino acids with NBD-F
> (4-fluoro-7-nitrobenzofurazan). In some papers I've read, these
> derivatives are stated to be very stable. In other papers, they are said
> to be stable for up to two days when stored in the dark in a refrigerator.
> Does anyone know what the best storage conditions are? Although this is
> just a guess, I would think that evaporating the samples to dryness under
> nitrogen (or with a SpeedVac), and then storing them in a freezer, would
> increase their storage life.
I have no experience specifically with NDB-F, but with some similar
compunds. They tend to be unstable and light sensitive before the
labeling reaction, while labelled products are reasonable stable. For
long term storage of labeled amino acids (rather than proteins), drying
by lyophilization or in a speed vac might be tried, but for a couple of
days it is probably easier to keep them in the fridge, with adequate
precautions against microbial growth (azide, merthiolate or ethanol for