Bill Melchior wmelchior at ntet.nctr.fda.gov
Tue Sep 21 16:11:34 EST 1993

In article <1993Sep20.212825.17557 at ohsu.edu>, nishir at ohsu.edu writes in 

> Solution II (good for about 2 weeks)              
> To make 100 mls: 
>    0.8 g NaOH (0.2 M) 
>    10 mls 10% SDS (1%) 

Plasmid protocols frequently call for making this fresh (eg, Maniatis et
al).  I, on the other hand, haven't seen any problems with a solution well
over a year old (stored in a polythylene bottle as suggested by Kieser in
Plasmid 12:19-36, 1984, who does NOT suggest making it fresh).  Birnboim,
Meth. Enz. 100:243-255, 1983, says, "The shelf life at room temperature is
about a week or longer, depending upon the source of SDS; ...."  I'd like
to know if nishir or anyone else has actually had bad experiences with old
alkaline SDS, or is it just folklore?  What happens when the solution goes 

Comments welcomed; Bill
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