[Histonet] Hard water.

[Rene J Buesa]

First of all I want to strongly encourage you to talk with your manager to try to eliminate the preparation of NBF in house. Formalin, as you perfectly know, is an extremely dangerous substance and any extra contact with it should be avoided. Spending some extra money in buying pre-filled vials with NBF is always worth it, because there is no price to your health.
Regarding your question you are adding your chemicals and determining the pH of your solution. NBF is used to fix the tissues and not to be used in a subsequent chemical analysis where all the components need to be known. This means that the purity of the water to prepare NBF is of little consequence in fixation, unless you are going to use the fixed tissues to determine some types of metals, in which case you may be incorporating those metals from the water into the tissues.
For IHC or FISH you are measuring organic components and I know of no interference with water minerals during fixation.
In any event, when you are adding your neutralizing chemicals and reach the desired pH that pH value is including any chemicals in the tap water and their contribution, if any.
Again, the ideal situation is to buy pre-filled vials with NBF. Do you in your lab determine formalin levels in the air and on the personnel?
René J.
 
 
 
 
--- On Wed, 3/28/12, MRI <matthew.ibbs <@t> wco.pl> wrote:


From: MRI <matthew.ibbs <@t> wco.pl>
Subject: [Histonet] Hard water.
To: histonet <@t> lists.utsouthwestern.edu
Date: Wednesday, March 28, 2012, 2:39 AM


Dear all,

In theory, we should all be using distilled or deionised water for making our formalin (assuming we don't buy it pre-prepared).  However, I know that some labs in my area are using tap water.  The water in our area is very hard ( >4.5 mol/m3 25°d) though it is pH neutral, and I'm curious if anyone knows what effects this may have on immuno and in-situ.
In our lab, we buffer our formalin according to the method in "Theory and Practice" by Bancroft and Gamble so I'm assuming others in the area do too... but I could be wrong, and I'm too frequently an optimist.
Should the buffers counteract negative effects from the minerals in the water or will they exacerbate the situation and add to the hardness and reduce the pH level?
Any ideas?

Thanks in advance,

Matthew.

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