Been reading COAs for a few months and something keeps bugging me. Everyone treats the HPLC number like pass/fail. 98 and up good, under 95 bad. Almost nobody looks at what the remainder actually is.
At work we never get one number back for a water sample. Every contaminant gets its own result against its own limit, because a sample can look clean overall and still fail on lead alone. Total purity on its own would get you laughed out of a compliance review.
So is there a standard list of what shows up in that 2% for synthetic peptides? Truncated sequences, oxidation, that kind of thing? And does it matter if it's one big peak or a bunch of small ones. Seems like it should.