In no way I am a chemistry major, so please forgive me if my question seems stupid. I just need a way to find the "equivalent $\mathrm{pH}$" of $\mathrm p[\ce{Cu^2+}]$ if that makes any sense to you.
I'm making a paper about a transistor that can sense ions (ion-sensitive field-effect transistor); i.e. it's a potentiometric transistor. I was able to simulate voltage values with respect to $\mathrm{pH}$ activity in a simulation software named LTspice, but in order for this paper to be passable to whoever shall evaluate it, I must compare my data with a preexisting experimental data.
The only experimental data that I have is from my co-advisee. He measured the voltage values with respect to $\mathrm p[\ce{Cu^2+}]$ $(\ce{CuCl2 · 2 H2O}).$ I think it wouldn't be proper to compare the voltage vs $\mathrm{pH}$ graphs and voltage vs $\mathrm p[\ce{Cu^2+}].$
So, I figured that if I can express $\mathrm p[\ce{Cu^2+}]$ to its equivalent $\mathrm{pH}$ (I don't think this is possible and makes any sense), then I'd be able to compare the two graphs.