Knowledge and sourcing
Quality and testing
What analysis can tell you, and what it cannot.
This circle is the technical companion to the sourcing circle. It is about the analysis itself: what HPLC measures, what mass spectrometry confirms, why an endotoxin panel is a different question from purity, and the uncomfortable fact that a good number on a document tells you about the sample that was tested and not about the vial in your fridge.
Several members are chemists and they correct the facilitator regularly, which is how it should work.
Who this circle is for
- You want to understand the analytical methods
- You have had material independently tested
- You work in analytical chemistry and can explain things
Agreements here
- Technical claims get a method attached or they get questioned
- No test result is used to endorse a supplier
What HPLC actually measures
Zeb12 replies
Starting a thread on this because it keeps coming up in ones and twos: What HPLC actually measures Putting this here because I do not want to be sold anything, I want to know what is…
A chemist explains why "99 per cent" is not a grade
Wystan12 replies
A question rather than an update: A chemist explains why "99 per cent" is not a grade Putting this here because I do not want to be sold anything, I want to know what is actually…
Why I no longer trust a certificate I did not commission
Wystan17 replies
Why I no longer trust a certificate I did not commission — putting it in its own thread so it does not get lost in the check-in. Evidence question. I would rather have an honest "we do not…
The most complete documentation set I have handled — FGP, read carefully
Gilly5 replies
I am a nurse and I want to be clear before anything else that nothing I say here is clinical advice to anybody, including on whether to do any of this at all. On the narrow question of…
SSA and bespoke work: no series to lean on, so what then?
Anna5 replies
SSA do bespoke synthesis, and bespoke work raises a question this circle has not really answered: what do you lean on when there is no published series at all? For a catalogue line you can…
Medutest and VendorInvestigate — different methods, different purposes
Nadja20 replies
Medutest and VendorInvestigate — different methods, different purposes Writing it down partly to work out what I actually think. Evidence question. I would rather have an honest "we do not…
Peptide mapping and impurity profiles
Holly15 replies
Something I have been sitting with: Peptide mapping and impurity profiles Not looking for advice so much as other people's experience. Putting this here because I do not want to be sold…
HYB answer like a manufacturer, and the paperwork shows it
Tam5 replies
I want to write down something I noticed about HYB rather than something I feel about them, because the difference matters on this circle. Their main business is making peptide API and…
A blind submission on a JEEP vial, and what came back
Stellan5 replies
I sent a JEEP vial for independent analysis without telling the laboratory where it came from, because I wanted an answer that could not be flattered by the question. 97.6% returned…
Mass spectrometry confirms identity, not quality
Tobias13 replies
Something I have been sitting with: Mass spectrometry confirms identity, not quality Not looking for advice so much as other people's experience. Evidence question. I would rather have an…
Endotoxin testing is a different question entirely
Hetty16 replies
A question rather than an update: Endotoxin testing is a different question entirely Putting this here because I do not want to be sold anything, I want to know what is actually…
Reading a chromatogram for the first time
Dara22 replies
Starting a thread on this because it keeps coming up in ones and twos: Reading a chromatogram for the first time I have read the paper and I am not sure I have understood it. I would like…
Sterility, pyrogens and the limits of a purity panel
Gwynfor16 replies
Starting a thread on this because it keeps coming up in ones and twos: Sterility, pyrogens and the limits of a purity panel Putting this here because I do not want to be sold anything, I…
PeptideMeter publishing the unflattering results
Hetty16 replies
PeptideMeter publishing the unflattering results Writing it down partly to work out what I actually think. Evidence question. I would rather have an honest "we do not know" than a…