Go Back   Science Forums Biology Forum Molecular Biology Forum Physics Chemistry Forum > Molecular Research Topics Forum > Protocols and Methods Forum
Register Search Today's Posts Mark Forums Read

Protocols and Methods Forum Post Any Protocol, Method, Technique, Procedure or Tips / Troubleshooting for any Molecular Biology Technique.


question about phenol/water saturated solution

question about phenol/water saturated solution - Protocols and Methods Forum

question about phenol/water saturated solution - Post Any Protocol, Method, Technique, Procedure or Tips / Troubleshooting for any Molecular Biology Technique.


Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 02-09-2008, 02:17 AM
Z.L. K
Guest
 
Posts: n/a
Default question about phenol/water saturated solution



Hi all,
I have a question with regard to the phenol/water saturated solution. I
didn't add any acids into it when i made it, when i test the pH of the
aqueous phase it said below 5 with the pH paper. the phenol was a fresh one
from some commercial company back then. currently the pH of the aqueous
phase is still the same after half a year sitting in the cold room at 4 C.
Today my labmate brought up a question for me and asked me what acid I added
into to to bring down the phenol solution pH. I told him I didn't add
anything. based on my understanding from reading online literatures before,
phenol is an organic acid and its pH stays low unless you use some buffer to
bring it up to the point you want it to be (such as pH 7 for extracting
DNA). I wonder if my understanding is correct or not, as i couldn't find any
detail online information now, which is weird.

My question here then should include two parts: 1, i have had RNA extracted
with this phenol/water saturated buffer (well then it's from the in vitro
transcription reaction, quite pure an RNA yield anyway), does it mean that
the water-saturated phenol really has the right pH to extract RNA (just to
answer my labmate's question); 2, if not, what acid should be used in
adjusting the pH?

Thanks!

z.
Reply With Quote
  #2  
Old 02-09-2008, 09:27 PM
DK
Guest
 
Posts: n/a
Default question about phenol/water saturated solution

In article <[Only registered users see links. ].net >, "Z.L. K" <[Only registered users see links. ]> wrote:

Your understanding is correct. Phenol = carbolic acid.


IIRC, yes, acidic phenol is recommended for RNA extractions (as opposed
to the tris-equilibrated solutions used for DNA).

DK
Reply With Quote
  #3  
Old 02-11-2008, 01:05 AM
David F. Spencer
Guest
 
Posts: n/a
Default question about phenol/water saturated solution

Z.L. K wrote:

The classic name for phenol is carbolic acid and it is indeed a very weak acid,
pka of a little under 10, and pH of a water solution of about 6 or less.
I wouldn't trust pH paper with phenol but instead would use a pH meter.
For protocols where RNA is desired but not DNA, the usual strategy is to have
the solution contain an acetic acid/sodium acetate buffer (say 0.3M) at about pH
4.5, and use phenol equilibrated against a similar buffer.
Your approach is essentially the same, although as with any method, using
unbuffered solutions will occasionally lead to unpredictable results.

David Spencer
Reply With Quote
Reply

Tags
phenol or water , question , saturated , solution


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
question about making sodium ortho-vanadate stock solution Z.L. K Protocols and Methods Forum 4 10-20-2009 12:26 PM
Cylindrical wave, wave equation, and mistakes h_v_ansari@yahoo.com Physics Forum 2 10-26-2006 01:47 AM
Sci.chem FAQ - Part 6 of 7 Bruce Hamilton Chemistry Forum 0 01-15-2004 09:12 AM
piranha solution not powerful enough? Chemistry Forum 6 07-23-2003 07:03 PM


All times are GMT. The time now is 05:08 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright 2005 - 2012 Molecular Station | All Rights Reserved
Page generated in 0.13418 seconds with 16 queries