[Meta] proposal — a flair for sequence posts
proposal — a flair for sequence posts — with the counter-argument included, because I find it fairly persuasive.
Every claim I could trace in this board went back to about four papers. That was a sobering afternoon.
Bought small, tested identity first, and only then thought about anything else. That order felt right.
Why identity, not purity, is the test to buy here.
This is a short peptide with a published sequence. Synthesis is not difficult, which means the market is wide and the analytical question shifts. A high area-percent figure tells you the sample is homogeneous; it does not tell you the homogeneous material is the sequence you ordered.
Mass spectrometry, with the theoretical mass alongside the measured one, converts a purity claim into an identity claim. It costs a little more and it answers the question that actually matters. Ask for it, and ask suppliers whether they can provide it before you order — the answers are informative in themselves.
Research-use-only material is not approved for human use and nothing here should be read as a recommendation to use it.
best — the order this archive was captured in
Purity by area percent tells you the sample is homogeneous. Mass spectrometry tells you what the homogeneous thing is. For a short peptide, the second question is the one worth paying for.
Assumed regulatory status was static and it was not. Checked again this year and the answer had changed where I live.