1 reply to this topic

[thc]

Hi all,

I want to prepare an enriched media with different pHs in a large range (3-11).  I have looked at several papers, but most remain ambiguous about details.  Is there a standard method available for adjusting media pH?  

I plan to autoclave the media first, then adjust with concentrated acid or base (5 M HCl or 5 M NaOH).  Is this a good way to go about it?  Do I need to filter sterilize concentrated acid/base or is it sterile already (being such extreme pH).  I worry because the acid might dissolve the filter and mess things up.  

Thanks.

[protolder]

thc, on 17 July 2011 - 03:30 PM, said:

Hi all,

I want to prepare an enriched media with different pHs in a large range (3-11).  I have looked at several papers, but most remain ambiguous about details.  Is there a standard method available for adjusting media pH?  

I plan to autoclave the media first, then adjust with concentrated acid or base (5 M HCl or 5 M NaOH).  Is this a good way to go about it?  Do I need to filter sterilize concentrated acid/base or is it sterile already (being such extreme pH).  I worry because the acid might dissolve the filter and mess things up.  

Thanks.

Hola, to me the best way could be add a buffer.As TB for E.coli has 0.1M phospate ph 7 or 7.5, you could prepare 0.1M PO4H2K and 0.1M PO4HK2 and mix in different proportions to get the wish pH, in any forum or any protocols page you will find tables, but I´m not sure that this strategie gets the extrems pHs that you want. Buena suerte