I have seen of course many posts and procedures that adjust the acid levels (PH) in the boiling flask. I understand that with a certain category of degredation reactions that are facilitated by oxygen that a higher PH can in theory lead to an enhanced inclination to oxidize.
However, I have to ask myself how on Earth can you measure this? I mean, a pH reading as far as I know is an indication of free hydrogen ions present at the moment the test is made. Then the question is, what reference are you using as a comparison and how exactly can this be tested so as to make the comparison relevent?
For instance when I take a pH measurement if I do not take the measurement at the same temp as the reference then the number is meaningless. Tap water generally is fairly nuetral in pH, yet heat it up and you will see a higher number of free hydrogen ions present and any pH meter not set to compensate for temperature via a special circuit (a crude but effective work around) will show the water to be a higher acidity. Let the water cool to room temp and the pH level returns to normal. So in the case of adding an acid to the boil, by what means do you test the compound first to see if it is already at the desired pH or not?
As far as oxidation occuring then on already distilled compound presumably because of an excess of free hydrogen ions facilitating oxidation of an already sensitive compound I must admit that I have seen numerous well intentioned and maybe even 100% accurate suggestions that this is occuring because of improper pH conditions either in the boil or post. The question I have for the community again is that how exactly can this be measured? If the presence of free H ions is a measure of acidity and of course there are millions of pH testers spanning a range of human activities, then why is the compound itself not tested for pH assuming that pH can indeed influence oxidation of the compound outside of the boil at ambient? The answer must lie in either the impractical nature of testing the compound itself for pH OR more likely there is simply no reference established as a basis to measure from. Currently it seems the reference being hinted at refers to water as the standard and therefor room temp as the reference against to measure.
What I am getting at here is there seems to be a good following who are adjusting pH levels but not first knowing where they are to begin with. Then when the pH adjustment does not impact oxidation I have seen again ideas to mitigate by further adding external compounds, but again without testing and knowing for sure what the levels are already and what the adjustment changes it into. Even worse from a technical point of view I have seen no paper, video, or reference that could be used in any realistic way to verify whether your additions 1) made a better difference, 2) made no difference, 3) made things worse. It is guesses and anecdotal observations and nothing wrong there but the underlying question with regards to all the pH adjustments being intentionally introduced; how do you know or not know how acidic your boil already is before you adjust it?