3 replies to this topic

[katenkak]

Hi guys!
I am new to immunohistochemistry field and got a suspicion that 0.3% H2O2 used to block endogenous peroxidase should be freshly diluted from stock, since my slides turned brown almost immediately after I added developing solution (mine H2O2 was prepared some weeks ago and was stored in refrigirator). Is that right? Should I prepare H2O2 right before I use it?
Thank you for answering!

Edited by katenkak, 16 April 2009 - 01:57 AM.

[gfischer]

katenkak, on Apr 16 2009, 04:56 AM, said:

Hi guys!
I am new to immunohistochemistry field and got a suspicion that 0.3% H2O2 used to block endogenous peroxidase should be freshly diluted from stock, since my slides turned brown almost immediately after I added developing solution (mine H2O2 was prepared some weeks ago and was stored in refrigirator). Is that right? Should I prepare H2O2 right before I use it?
Thank you for answering!

If the peroxide was in a clear bottle, it was definitely bad. Hydrogen peroxide is light sensitive. I don't see why you shouldn't be able to store it for a while, but make sure you protect it from light. If you don't have any opaque bottles, wrap one in aluminum foil. Also, I tend to prefer to use freshly diluted solutions, though I can't say whether it necesarily matters.

[katenkak]

Thank you,
I had my diluted H2O2 in 50 ml plastic tube, so it was definetely exposed to light, but strangely enough the stock solution is not in a dark bottle (white opaque). I'll try freshly diluted peroxide as you do.
Best



If the peroxide was in a clear bottle, it was definitely bad. Hydrogen peroxide is light sensitive. I don't see why you shouldn't be able to store it for a while, but make sure you protect it from light. If you don't have any opaque bottles, wrap one in aluminum foil. Also, I tend to prefer to use freshly diluted solutions, though I can't say whether it necesarily matters.
[/quote]

[Carlton H]

You should be able to store H2O2 for a while, so long as you're not opening and closing the bottle that much. Remember that H2O2 is HIGHLY reactive and will oxidize just about anything (an exaggeration, but not much of one), so if you leave it open or just keep opening / closing the bottle it will go bad.