[Discussion] the related substances advice in here is 3 years out of date
the related substances advice in here is 3 years out of date. It is the sort of thing everyone half-believes and nobody writes down. 3 years — those are the numbers, and they are the ones I am willing to defend. Related substances itemised individually is a much stronger document than a single total, because it tells…
The PDF creation date being later than the analysis date is usually a re-issue or a re-export. It is worth one question and it is not evidence of anything on its own.
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Are the related substances itemised or is it a single total?
Net peptide content is the fraction of the powder that is actually peptide once counterion, water and residual solvent are accounted for. A 99% pure acetate salt can still be about 85% peptide by mass.
Area percent or net peptide content? They answer different questions.
Batch number and date of analysis, are both on there?
What does the method line actually say? Not the technique — the column and the gradient.
Disagree that a lower number is automatically worse. A conservative claim that survives testing is worth more than an optimistic one that does not.
net peptide content and purity are two different numbers on the same vial
LC-MS gives you identity; UV purity gives you a relative quantity. A document with the first and not the second, or the reverse, is answering half the question.
Yes — and the reason to ask for the whole page is that the interesting parts are the ones people crop out to fit a screenshot.
the lot on the vial has to match the lot on the page