HEPES/MES in pH adjustments of tissue culture media

Christian Belanger 4104CBEL at vm1.ulaval.ca
Fri Dec 10 09:18:10 EST 1993

In article <CHsupD.JMu at umdnj.edu>
bawagan at umdnj.edu (Hinayana Bawagan) writes:
>    I need to test the sensitivity of my virus to different pHs. HEPES and MES
>are used for pH adjustments of tissue culture media.  I do no know how to go
>about preparing the media.  Is there some kind of calculation involved that
>this amount of the chemical will give me this pH?  The media has to be sterile
>so I just can't have the electrode of a pH meter dipped into it while I am
>adding some adjuster dropwise.
>    I apologize for asking if the answer is obvious and too basic to be
>asked in the net.
>    Thank you.
   I used minimal medium that pH is adjusted to 5.8 with MES.  This media is
used to grow bacteria (A. tumefaciens).  I prepared 1.0M stock of MES like
  1. Weigh 10.5g of MES in 25ml of water
  2. Adjust pH to 5.8 with NaOH 5N
  3. Complete with water up to 50ml.
  4. Readjust the pH if necessary.
  5. Sterilized by filtration.
4ml of this stock is added (under steril conditions) to the autoclaved medium
(final vol: 100ml).  That give a medium pH5.8, 40mM MES.
I never used HEPES (sorry...).
     Your French Net-Reader,
         Christian Belanger
         Universite Laval, Dept. de Phytologie
         Quebec, Canada, G1K-7P4.
         (418) 656-2131 Ext.6785, FAX (418) 656-7856

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