[Lab] QYB BPC — Medutest came back 99.2% against a claimed 99.0%
Right: QYB BPC — Medutest came back 99.2% against a claimed 99.0%. I paid for this one myself, nobody sent me anything, and the receipts are in the comments.
The numbers the title promised, since a headline without them is worthless: 99.2% and 99.0%. Everything below is context for those.
On inter-lab disagreement, which generates more heat here than anything else.
Two services running different gradients, integrating differently, at possibly different wavelengths, will not produce identical numbers on the same material. A point either way is ordinary. Half a point is close agreement.
The productive response to a gap that size is to post both results with both methods and let the log accumulate. The unproductive response is to pick the lower number, call it the truth, and open a dispute. Members have done the first for long enough now that the bands in the vendor tables are genuinely informative.
How to build a series that means something, if you are going to spend money on testing anyway.
Three tests on one lot tells you about your measurement. Three tests on three lots, spread over a year, tells you about a process. The second is the one worth paying for and it costs the same.
Buy small, keep the batch numbers, send one vial per lot, and post each one with the claim next to it. After four or five you have something no individual review can give you: a band, a direction and a date range. That is what the source pages are made of.
Please do not ask me what dose you should be on. I genuinely do not know and neither does anyone else here.
- QYQYB source pageChinaPeptides Co., Ltd. (QYAOBIO) · Shanghai · 93% here, rank 11 · shop at qyaobiopeptides.com →
nofollow and sponsored; nobody here is paid for it.best — the order this archive was captured in
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.
Correction: that is the claimed figure, and the measured one is the higher of the two in your own screenshot.
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
a result with no batch number is about a vial nobody can identify
Small fix — same supplier, different lot. The two rows in the log are not the same batch.
Correcting myself: I quoted net peptide content against somebody else’s area percent. Not a comparison.
Left up and added to the vendor source page log. Thanks for paying for it and posting it.
area percent unless the report says otherwise
Agreed on quoting the claim alongside the result. Half the arguments here are two people comparing to different reference numbers.
Have now spent more on testing than on some of the orders. No regrets — the log is the reason I can buy without agonising.
Have now spent more on testing than on some of the orders.
This is why the template has a batch field. Without it the result is about a vial nobody can identify.
Batch number and date of analysis?
I would not post that as a finding. It is a single result and the template asks you to say so.
Not convinced by the comparison. Different services, different gradients, and you are treating one as ground truth.
That service reports area percent by default. Worth stating, since the thread has been comparing it to a mass figure.
SGN came back 97.5% on a claimed 97.0%, which is agreement not a discrepancy
Sent a vial in specifically to check a supplier’s claim after a good experience. It matched. Boring result, worth logging.
FGP BPC, batch matched the paperwork, PeptideMeter came back 98.6% against a claimed 98.0%. Paid for it myself, posting it because the log is only worth anything if people do.
- 1If the report gives a mass spectrum as well as UV purity, say so. Identity…11 comments in this branch · started by u/lift_heavy_things