SOB Medium: Why add Mg late?

Jeff Lawrence lawrence at
Sun Jul 9 12:53:49 EST 1995

In article <3tg6g3$ov5 at>, Nigel Kenward
<mbxnjk at> wrote:

> I understand that if you put the Mg ions in prior to autoclaving, there 
> is a risk that the Mg will precipitate out and make the solution cloudy.
> I've never risked it so I can't confirm whether it's true or not !
> Nigel Kenward

this is, for the most part, true.  Mg++ requires a chelating agent, like
citrate, to stay in solution at high temperatures.  without it, it's
likely to precipitate and it's murder driving it back in.  believe me, i


jeff lawrence
lawrence at

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