[PeptideMeter] QSC tirz — 97.1%, second sample from the same batch
Short version of the title, which is already short: QSC tirz — 97.1%, second sample from the same batch. Longer version underneath.
Pulling the figures out of the title: 97.1%. All of it is written down as it happened rather than reconstructed.
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.
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.
Not medical advice, obviously, and nothing here is approved for human use. One person with a spreadsheet.
- QSQSC source pageQingdao Sigma Chemical Co., Ltd. · Qingdao · 95% here, rank 7 · shop at qingdaosigma.com →
nofollow and sponsored; nobody here is paid for it.best — the order this archive was captured in
A series across separate lots estimates a process. Repeat tests on one lot estimate the measurement. Both are useful and they answer different questions.
Did the vial lot match the paperwork lot?
Did the vial lot match the paperwork lot?
Disagreeing with this line: that gap is ordinary variance, not a contradiction between the lab and the certificate.
Disagree that this is a discrepancy. 97.1% against a claimed 97.0% is inside ordinary inter-lab variance in either direction.
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.
Agreed — the template exists because a result without the batch and the claim is unanchored.
if you are going to test, test the thing you actually received
Small fix — same supplier, different lot. The two rows in the log are not the same batch.
Left up and added to the vendor source page log. Thanks for paying for it and posting it.
[deleted]
inter-lab variance runs a point or two, plan your outrage accordingly
First result I ever posted here got asked for the batch number and the claim. Fair, and my posts have been better ever since.