Manjula,

I would look at some of Sergey Dikalov's papers.  I attached a protocol from his group that summarizes different methods/conditions for detecting ROS in cells and tissues.  

Papers from the Medical College of Wisconson EPR group, Dartmouth, Iowa, and Ron Mason's group all have published extensively on this topic.  Emailing one of these groups or Dikalov for direct questions about established protocols would be a good idea.

Robert   

I agree with Robert -- contact folks who have done this. He mentions Iowa -- Garry Buettner has done this kind of work and is very helpful and approachable. You can find his email address at the U Iowa web page (I don't have it on me at the moment). 

Dear Manjula

I suggest to see papers of Komarov DA. For example this one: http://www.ncbi.nlm.nih.gov/pubmed/22162021

Tatyana

I did performed an EPR experiments on mice brains, I just homogenized the brains using liquid nitrogen and place the liquid obtained in a flat quartz cell.

It worked perfectly 

I recommend to use DHE with HPLC detection of oxyethidium (adduct of superoxide and dihyroxyethidium) as independent control of EPR experiments. Fe ions with tissue lysates are major problem they can oxidase spin labels at least in my experience.

You are using the wrong trap! DMPO-OH and DMPO-OOH can interconvert. Try with DEPMPO instead

More about DMPO, on my blog:

https://steemit.com/steemstem/@alexs1320/answering-9-rg-quest

Dear all, thank you for your answers.

As I am not working on this project anymore I do not need help but feel free to continue the discussion on this topic.

I trapped nitric oxide and I've got many remarks and observations.