Oh, it's ok, but I need...But thank you for your answer, because it could be the best you can give to a referee when he asks you more measurements in a revision.
I don't think if is possible to measure the pH difference between autophagosomes and autophagolysosomes…because both are "acidic compartment". I think that if you want to know the "state of autophagy" you should measure maybe the activity of cathepsines or I know that there are some "marker" that would help you to discriminate between early lysosomes and late lysosomes…. nevertheless the pH of that structures is 4.8-5.5, more or less.