why does nobody talk about test results
Asking properly rather than in a comment on somebody else’s thread: why does nobody talk about test results.
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.
Have now spent more on testing than on some of the orders. No regrets — the log is the reason I can buy without agonising.
Happy to answer the boring questions. Those are usually the ones worth asking.
best — the order this archive was captured in
Area percent and net peptide content are different measurements and most reports give one. Quote which, or the comparison downstream is meaningless.
Area percent and net peptide content are different measurements and most reports give one.
Adding the boring but useful bit: say whether you paid for it. It is the basis of the whole log.
the log is cumulative, that is the whole value of it
Area percent and net peptide content are different measurements and most reports give one.
This is why the template has a batch field. Without it the result is about a vial nobody can identify.
This is why the template has a batch field.
saskia_mwangi is right that the band matters more than the peak. Consistency across lots is the finding.
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if you are going to test, test the thing you actually received
one result is a data point, agreement between two services is evidence
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.
Not convinced by the comparison. Different services, different gradients, and you are treating one as ground truth.
Batch number and date of analysis?
What was the claim on the certificate you are comparing against?
Area percent or net peptide content?
date of analysis matters as much as the number
CPC BPC, batch matched the paperwork, Janoshik came back 99.3% against a claimed 98.5%. Paid for it myself, posting it because the log is only worth anything if people do.
Same. The KP results have been sitting in a tight band across lots, which is the useful shape.
vendor, compound, batch, service, result — that is the template
Split one vial between VendorInvestigate and PeptideMeter. The two numbers were within half a point of each other and I stopped worrying about which lab to trust.
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.
Is that the same lot as the one in the thread from last month?
Kept every report as a PDF with the batch in the filename. Two years in, it is the most useful folder I own.
net peptide content if the report gives it, and say which you are quoting
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.
That service reports area percent by default. Worth stating, since the thread has been comparing it to a mass figure.
the trend across lots is worth more than any single figure
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.
A series across separate lots estimates a process. Repeat tests on one lot estimate the measurement. Both are useful and they answer different questions.
Disagree that this is a discrepancy. 99.6% against a claimed 99.0% is inside ordinary inter-lab variance in either direction.
Agreed on quoting the claim alongside the result. Half the arguments here are two people comparing to different reference numbers.
- 1Area percent and net peptide content are different measurements and most…8 comments in this branch · started by u/camila_mensa
- 2Inter-lab variance on this assay runs roughly a point either way, driven…6 comments in this branch · started by u/runa_wikstrom