Estimate Pe/Redox Potential from O2

[kishu5694]

Hello,

I am trying find the Pe value for Opensystem. As we know Oxygen exchange occur between aqueous solution and atmosphere. So,

1) How can I estimate the value of Pe from from O2
2) Or if I fix the value of Pe then How can i find Concentration of O2 in solution?

It would be good for me if you can also specify the formula/equation for measuring it theoretically.

Thank you in advance