Urea-containing buffers: How long can I store them?

[packard at kersur.net]

>Viraj Master wrote:
>> 
>> Hello all,
>> 
>> I am using the Qiagen pQE series of vectors to express proteins.  There
>> are two buffers which I use a lot, Buffer B and Buffer C.
>> 
>> These contain:
>> 8M urea
>> 0.1M NaH2PO4
>> 0.01M Tris
>> 
>> Buffer B is at pH=8
>> Buffer C is at pH=6.3
>> 
>> I have been told that I must make these buffers up **fresh** each time
>> prior to use.  I would like to be able to prepare batches of these
>> buffers and store them.  Does anybody know whether this can be done and
>> not affect the protein prep?  If so, are they stored in the cold, or at
>> room temp?  For how long can they be stored?
>> 
>> Many thanks,
>> 
>> Viraj
>> 
>> Viraj Master PhD
>> Dept of Organismal Biology
>> University of Chicago
>
>

	I work for a biotech company, and we use 8M urea buffers on
occasion.  We assign a 3 day expiration on these buffers.  I hope this
helps.

					Kevin M Packard