[Histonet] pH of EDTA

[Katri Tuomala]

Hi Donna,
We use in-house EDTA buffer for retrieving some antigens. We have noticed, 
that the pH decreases as the buffer gets older. We make a litre at a time 
and use it within the week. It seems this buffer is not stable and maybe pH 
needs to be checked and adjusted each time you use it. Maybe you can adjust 
the pH after diluting it for use, with very dilute sodium hydroxide.
I find EDTA buffer bothersome, if your detection system is avidin based, 
since it brings out the endogenenous biotin in many tissues. We end up doing 
a biotin block on all the EDTA retrieved tissues.
Good luck!

Katri
Katri Tuomala
Hamilton, Ontario, Canada

----- Original Message ----- 
From: "donna rossi" <djmr55 <@t> hotmail.com>
To: <histonet <@t> lists.utsouthwestern.edu>
Sent: Thursday, November 02, 2006 5:50 AM
Subject: [Histonet] pH of EDTA


>
>   We are having a problem with EDTA pH 8.0 from LabVision.  When we take
>   the pH of the concentrate it is 8.O.  When we dilute it as recommended
>   it  changes  to  6.0.   Lab  Vision  replaced our bottles  but the new
>   bottles  also  come  out  to  6.0 when diluted.  We took the pH of the
>   Distilled  water here and got 7.1.  What could be the problem.?  Do we
>   adjust  the distilled water to a higher pH?  How do we do that?  Do we
>   then  need to validate all of our antibodies that use EDTA  using the"
>   new"  EDTA?  We have  also had this problem with Zymed EDTA but not as
>   radical  a  difference as  the  Labvision.   It  was suggested that we
>   switch  to  ready-made  EDTA but we have a quantity of this and do not
>   have  the room to store multiple big bottles of this retrieval buffer.
>   Can someone give me a suggestion?  Thanks,  Donna, SRHS
>     _________________________________________________________________
>
>   [1]Use your PC to make calls at very low rates
> References
>
>   1. http://g.msn.com/8HMAENUS/2749??PS=47575
> _______________________________________________
> Histonet mailing list
> Histonet <@t> lists.utsouthwestern.edu
> http://lists.utsouthwestern.edu/mailman/listinfo/histonet