research peptides — 22 things I got wrong before I got it right
research peptides — 22 things I got wrong before I got it right. I have gone back and forth on this for months.
Net peptide content accounts for counterion, water and residual solvent. On some of these compounds the gap between purity and net content is substantial and entirely honest.
For any compound with a thin testing history, identity is the first question. Mass spectrometry against a theoretical mass answers it; an area-percent purity figure does not.
Naming in this space is inconsistent. Several widely used names map to more than one molecule, so a catalogue number and a sequence beat a common name every time.
Please do not ask me what dose you should be on. I genuinely do not know and neither does anyone else here.
best — the order this archive was captured in
Left up. Identity-first reasoning with a method stated, which is the standard for this board.
Disagree — that name refers to at least two different molecules depending on who is selling it. The thread needs to be specific.
That method was developed for a different compound class and would not resolve the impurities you are asking about.
Bought small on anything without a testing history here. That rule has never once cost me anything.
purity methods differ between compound classes
Purity methods differ by compound class. A gradient and wavelength developed for one peptide will not necessarily resolve the relevant impurities of another.
if nobody has tested it here, that is a fact about us, not the compound
identity before purity, every time, for anything unusual
Has anyone here tested that compound at all?
ask which lines are actually stocked rather than made to order
Storage conditions came back specific rather than generic when I asked. That told me somebody had actually done stability work.
Yes. Nothing in this catalogue is approved for human use and the board should keep saying so.
Small fix — that is net peptide content, not purity. Both are on the certificate and they differ substantially here.
Net peptide content on the certificate was well below the purity figure and both were honest. Chemistry, not deception.
Net peptide content on the certificate?
The three questions to ask before ordering anything from the long tail of a catalogue.
What exactly is it — catalogue number or sequence, not a common name, because several common names map to more than one molecule. How was identity established — mass against theoretical, ideally, rather than a bare purity figure. What are the storage conditions, stated specifically, with a state and a duration attached.
Then two commercial questions that save time: is this a stocked line or made to order, and what is the lead time in writing. All five are one email, and the shape of the reply tells you a great deal before any material moves.
What storage conditions did they specify?
- 1Purity methods differ by compound class. A gradient and wavelength developed…6 comments in this branch · started by u/sofia_petrescu