[Discussion] the TB-500 advice in here is 2 years out of date
the TB-500 advice in here is 2 years out of date, which sounds obvious until you try to state the evidence for it.
To save the first four comments: 2 years.
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.
Purity methods differ by compound class. A gradient and wavelength developed for one peptide will not necessarily resolve the relevant impurities of another.
Would rather be corrected in public than confident in private.
best — the order this archive was captured in
Storage guidance that names a temperature, a state and a duration reflects actual stability work. Generic guidance usually reflects a template.
I would not treat catalogue breadth as a quality signal. It is a business decision, not an analytical one.
Asked for identity confirmation on an unusual line and got a mass spectrum with the theoretical mass alongside. That is the answer I now look for everywhere.
Research-use-only material is not approved for human use. In this catalogue that covers essentially everything, which is why the board discusses material and analytics rather than outcomes.
Careful — that is a claim about efficacy and there is essentially no human evidence behind it.
catalogue depth is not the same as catalogue quality
the sequence is the product, everything else is packaging
That method was developed for a different compound class and would not resolve the impurities you are asking about.
That result is an area percent from an unspecified method, which is not the same as the identity confirmation being discussed.
Not convinced. A purity figure without a stated method is not comparable to one that has a method attached.
Standing reminder: research-use-only material is not approved for human use, and no outcome claims without evidence.
Storage conditions came back specific rather than generic when I asked. That told me somebody had actually done stability work.
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.
On the thin testing history in this board, and what to do about it.
Most of the compounds discussed here have a handful of independent results across the entire site, and several have none. That is a fact about how few members have paid for testing, not a judgement about the material.
What follows: buy small, test identity first for anything unusual, and post the result even when it is unremarkable. The vendor source pages are built from exactly these submissions, and the compounds with the thinnest coverage are the ones where one more entry changes the picture most. Research material is not approved for human use, so what this board can usefully build is an analytical record.
the same name covers several different molecules in this space
Push back: handling advice from one compound does not transfer to another just because both are peptides.
Ordered under a name that turned out to cover two different molecules. Nobody’s fault but mine for not asking.
Ordered under a name that turned out to cover two different molecules.
This is the rule for anything unusual. Identity before anything else.
This is the rule for anything unusual.
Adding the practical question — stocked or made to order, and what is the lead time.
purity methods differ between compound classes
Sent an unusual compound to VendorInvestigate because nobody on this site had ever posted one. 97.9% against a claimed 97.0%.
- 1For any compound with a thin testing history, identity is the first…8 comments in this branch · started by u/long_post_larry
- 2Research-use-only material is not approved for human use. In this catalogue…6 comments in this branch · started by u/escrow_evangelist