[Discussion] the batch advice in here is 3 years out of date
the batch advice in here is 3 years out of date. It is the sort of thing everyone half-believes and nobody writes down.
The relevant figures are 3 years, and they come from the same log I have kept the whole time.
Split one vial between Janoshik and Medutest. The two numbers were within half a point of each other and I stopped worrying about which lab to trust.
First result I ever posted here got asked for the batch number and the claim. Fair, and my posts have been better ever since.
I will update this if the picture changes rather than quietly leaving it up.
best — the order this archive was captured in
Date of analysis anchors the result to a manufacturing period. A two-year-old result is evidence about two years ago and should be read that way.
Date of analysis anchors the result to a manufacturing period.
santiago_rasmussen is right that the band matters more than the peak. Consistency across lots is the finding.
HJ BPC, batch matched the paperwork, VendorInvestigate came back 97.6% against a claimed 97.5%. Paid for it myself, posting it because the log is only worth anything if people do.
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.
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That service reports area percent by default. Worth stating, since the thread has been comparing it to a mass figure.
Homopeptide came back 99.1% on a claimed 98.5%, which is agreement not a discrepancy
Correcting myself: I quoted net peptide content against somebody else’s area percent. Not a comparison.
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.
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.
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.
a result with no batch number is about a vial nobody can identify
Same. The WWB results have been sitting in a tight band across lots, which is the useful shape.
- 1Fourth lot from the same supplier in the log now and the band has been tight…6 comments in this branch · started by u/cold_chromatogram_only