pHing sodium Acetate
Penny Greenwood
polyA-enriched RNA extraction procedure. If anyone has any ideas or advice on
how to achieve this please reply to the net.
Cheers Penny and happy little new netter Laurel.
Penny Greenwood
Martin Leach
GREEN...@AGRESEARCH.CRI.NZ (Penny Greenwood) wrote:
Glacial Acetic Acid
MArtin
--
..... Martin Leach Email:le...@mbcrr.harvard.edu
_|____ Dept. of Pharmacology Phone: (617) 638-5323
/ o / Boston Univ. School of Med. Fax: (617) 638-4329
_/ |-/__==/ 80 E. Concord St. (L603)
(BULLDOZER) \_ Boston MA 02118 "Not the old underpants on your
USA head.....WIBBLE" -BLACKADDER
p.s. try BioMOO (virtual biology on the internet - telnet
bioinfo.weizmann.ac.il 8888)
FJVA...@ukcc.uky.edu
the acetate. Then all you have to do is decide what it is that you want to
be 3M (the sodium or the acetate).
Cheers, Frank.
David Sang-shin Lee
> hi, We're having great difficulty getting 3M NaAc to pH 4.0, for use in a
> polyA-enriched RNA extraction procedure. If anyone has any ideas or advice on
> how to achieve this please reply to the net.
Perhaps you can start from the other direction....Start with acetic acid and
raise the pH with NaOH.
-------------------------------------------------------------------
David S. Lee (davi...@umich.edu) All opinions
HR6028, Kresge Hearing Research Institute expressed
University of Michigan here are
Ann Arbor MI 48109-0506 mine!
Andrew Cockburn
This is going to be about half HAc at this pH. You could figure it out and
add the appropriate amounts of HAc and NaAc, or you could do it the lazy
way:
Make up a 3M solution of HAc.
Make up a 3M solution of NaAc.
Mix the two until you get to pH 4.0.
This is assuming that it is supposed to be 3N Ac-, not 3N Na+.
Andrew Cockburn
USDA
Chris Noren
>The trick is to start with the acetic acid and pH it UP with
> the acetate. Then all you have to do is decide what it is that you want to
> be 3M (the sodium or the acetate).
>
The concentration given for a buffer refers to whatever is the buffering
component (i.e. acetate for NaOAc, tris for tris-HCl, HEPES for Na-HEPES
etc.). In order to keep the acetate constant at 3 M, you should start with
3 M acetic acid and (carefully!!) pH it upward with conc. NaOH.
--
Christopher Noren
New England Biolabs
(800)632-5227 ext 261
no...@neb.com
Tom Chappell
actually, the trick is to believe two very old (and probably by now
dead) chemists named Henderson and Hasselbalch and know that the pKa of
acetic acid has been precisely determined to be 4.76...
Tom Chappell
MRC Lab for Molecular Cell Biology
University College London
Clive Dennison
>From: a...@gnv.ifas.ufl.edu (Andrew Cockburn)
>Subject: Re: pHing sodium Acetate
>Date: 4 May 94 16:19:59 -0500
>Andrew Cockburn
>USDA
Or, why not start with HAc, that will be 3M when made up to volume, make up
nearly to volume, titrate with NaOH of arbitrary concentration and then make
up to volume. This approach works with most buffers and cuts down on the
number of weighings, etc.
Have pHun,
Clive - Biochemistry, Univ. of Natal.
daj
>>GREEN...@AGRESEARCH.CRI.NZ (Penny Greenwood) writes:
>>> hi, We're having great difficulty getting 3M NaAc to pH 4.0, for use in a
>>> polyA-enriched RNA extraction procedure. If anyone has any ideas or advice
>>on
>>> how to achieve this please reply to the net.
>>>
From my records, it requires glacial acetic acid to 15-20% of final
volume to get to pH5, so, I guess, make a 5-6M solution, pH this and
then diluted to 3M and check.
DAJ
David A. Johnston
Dept of Zoology, The Natural History Museum, Cromwell Road,
South Kensington, London SW7 5DB. England
(tel 071 9389297, fax 071 9388754, email d...@nhm.ic.ac.uk)
m...@biochem.su.oz.au
>hi, We're having great difficulty getting 3M NaAc to pH 4.0, for use in a
>polyA-enriched RNA extraction procedure. If anyone has any ideas or advice on
>how to achieve this please reply to the net.
>
Mark Smith
Dept. Biochemistry
Uni of Sydney
Sydney, Australia
kl...@mpimg-berlin-dahlem.mpg.de
Sodium acetate-acetic acid buffer (1 M), pH 3,6-5,8
Walpole, J.C.S. 105, 2501 (1914)
Na acetate, 3HOH, M.W.=136,09
......................................................
I 1M sodium I I
pH at 18"C I acetate I 1M acetic acid I
.................I.................I.................I
I (ml) I (ml) I
3,6 I 0.75 I 9,25 I
3,8 I 1.20 I 8,80 I
4,0 I 1,80 I 8,20 I
4,2 I 2,65 I 7,35 I
4,4 I 3,70 I 6,30 I
4,6 I 4,90 I 5,10 I
4,8 I 5,90 I 4,10 I
5,0 I 7,00 I 3,00 I
5,2 I 7,90 I 2,10 I
5,4 I 8,60 I 1,40 I
5,6 I 9,10 I 0,90 I
5,8 I 9,40 I 0,60 I
.................I.................I.................I
Live long and prosper....
Mathieu Klein