[Discussion] below spec is doing more work than we give it credit for
below spec is doing more work than we give it credit for. Change my mind, genuinely — I have no stake in being right about this.
First result I ever posted here got asked for the batch number and the claim. Fair, and my posts have been better ever since.
Split one vial between PeptideMeter and VendorInvestigate. The two numbers were within half a point of each other and I stopped worrying about which lab to trust.
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.
Research-use-only material is not approved for human use and nothing here should be read as a recommendation to use it.
best — the order this archive was captured in
The template is vendor, compound, batch, service, claim, result, and who paid. Every one of those fields exists because a result missing it has been argued about here before.
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.
Have now spent more on testing than on some of the orders. No regrets — the log is the reason I can buy without agonising.
That service reports area percent by default. Worth stating, since the thread has been comparing it to a mass figure.
area percent unless the report says otherwise
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.
Batch number and date of analysis?
Small fix — same supplier, different lot. The two rows in the log are not the same batch.
Tested three lots over a year rather than three vials from one lot. Cost the same and told me something completely different.
Sent a vial in specifically to check a supplier’s claim after a good experience. It matched. Boring result, worth logging.
Kept every report as a PDF with the batch in the filename. Two years in, it is the most useful folder I own.
QSC BPC, batch matched the paperwork, PeptideMeter came back 98.8% against a claimed 98.0%. Paid for it myself, posting it because the log is only worth anything if people do.
Correction: that is the claimed figure, and the measured one is the higher of the two in your own screenshot.
Which service, and did you pay for it yourself?
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.
split a vial across two services once and you will never argue about ground truth again
vendor, compound, batch, service, result — that is the template
That reading assumes area percent and net peptide content are the same number. They are not, and the report says which it is.
if you are going to test, test the thing you actually received
Is that the same lot as the one in the thread from last month?
A series across separate lots estimates a process. Repeat tests on one lot estimate the measurement. Both are useful and they answer different questions.
net peptide content if the report gives it, and say which you are quoting
What was the claim on the certificate you are comparing against?
- 1split a vial across two services once and you will never argue about ground…9 comments in this branch · started by u/noor_cardoso
- 2The template is vendor, compound, batch, service, claim, result, and who…6 comments in this branch · started by u/arne_restrepo