Media left at 37 C O/N?

[James Giddings]

Tim Eggleston wrote:
> The question regarding heating the RPMI media to 60 C brought to mind
> a question I've wondered about from time to time.  If media, such as
> DMEM or MEM, is left in a 37 C water bath O/N, will be ok to use it
> the next day.  I have always advised people to pitch it due to the
> possible degradation of L-glutamine, but I have always wondered how
> much degradation actually occurs, if any.  Thanks!
> 

IIRC Glutamine at 37 has a "half-life" of about 1 week, and 2 weeks at 
RT. Though other factors may affect the media's suitability for use such 
         as how any ammonium ions from glutamine breakdown are buffered 
by other components.