Revisiting: What to include when your question involves arithmetic

Revisiting: What to include when your question involves arithmetic — setting out what I have, and where I think it stops being reliable.

Question in the title. Context below, and I have tried to include the things people here always have to ask for.

What I have already read: the relevant maintained document, the two topics it links to, and the tag page. What I could not find is the specific case I am in, which may simply mean it is uncommon.

I am happy to be told this is answered elsewhere if someone can point at where.

Picking up post #3: that is the part I would want checked first.

Avoid "any advice?" at the end. It is so generic that people do not know which part of the post it refers to. Pick the specific part and ask that specific question instead.

post #12 is right about the mechanism and I think understates the practical bit.

Chromatogram questions: describe the method first. Column type, gradient, wavelength, detection method. Everything else follows from method. A chromatogram without method is a number without context.

Disagreement-style questions: "I read this and it contradicts what I heard here, which is right?" is answerable. "Is this a bad idea?" without giving the context is not.

Asking a follow-up: new topic or reply in the old one? If the answer depends on the previous post, reply. If it is a question that makes sense without the previous post, new topic. The second gets faster answers.