how much of what we believe about purity actually comes from below spec threads
Genuine question, and the title is the question: how much of what we believe about purity actually comes from below spec threads.
A series across separate lots estimates a process. Repeat tests on one lot estimate the measurement. Both are useful and they answer different questions.
Inter-lab variance on this assay runs roughly a point either way, driven mostly by gradient and integration. Two results inside that band agree; they do not disagree quietly.
Kept every report as a PDF with the batch in the filename. Two years in, it is the most useful folder I own.
Not medical advice, obviously, and nothing here is approved for human use. One person with a spreadsheet.
best — the order this archive was captured in
Chain of custody is why member-funded testing is worth more than a supplied certificate: the vial tested is the vial that arrived at a member’s door.
Careful with the trend claim. Four results over two years is a very sparse series to draw a line through.
Left up and added to the vendor source page log. Thanks for paying for it and posting it.
Split one vial between VendorInvestigate and Medutest. The two numbers were within half a point of each other and I stopped worrying about which lab to trust.
area percent unless the report says otherwise
area percent unless the report says otherwise
Adding the boring but useful bit: say whether you paid for it. It is the basis of the whole log.
Did the vial lot match the paperwork lot?
Tested three lots over a year rather than three vials from one lot. Cost the same and told me something completely different.
Is that the same lot as the one in the thread from last month?
Push back: three tests on one lot is one lot. It tells you about that lot and almost nothing about the next one.
Fourth lot from the same supplier in the log now and the band has been tight the whole way. That consistency is the actual finding.
If the report gives a mass spectrum as well as UV purity, say so. Identity and relative quantity are separate claims and the log tracks both.
Do you have the trace, or only the summary?
a result with no batch number is about a vial nobody can identify
a result with no batch number is about a vial nobody can identify
crp_curious is right that the band matters more than the peak. Consistency across lots is the finding.
if you are going to test, test the thing you actually received
Disagree that this is a discrepancy. 97.5% against a claimed 97.0% is inside ordinary inter-lab variance in either direction.
Not convinced by the comparison. Different services, different gradients, and you are treating one as ground truth.
inter-lab variance runs a point or two, plan your outrage accordingly
Sent a vial in specifically to check a supplier’s claim after a good experience. It matched. Boring result, worth logging.
Yes. Two services on the same batch is the strongest thing an individual member can produce, and it is not expensive.
I would not post that as a finding. It is a single result and the template asks you to say so.
I would not post that as a finding.
Agreed — and two services on one batch is the strongest thing any of us can produce individually.
Area percent and net peptide content are different measurements and most reports give one. Quote which, or the comparison downstream is meaningless.
the trend across lots is worth more than any single figure
- 1Fourth lot from the same supplier in the log now and the band has been tight…8 comments in this branch · started by u/coring_the_stopper
- 2Left up and added to the vendor source page log. Thanks for paying for it…6 comments in this branch · started by u/janoshik_junkie