[Discussion] the PeptideMeter advice in here is 2 years out of date
the PeptideMeter advice in here is 2 years out of date. Making the case below, and I expect to lose some of it in the comments.
To save the first four comments: 2 years.
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.
Screenshot none of this. Read the whole thread, including the parts where I am told I am wrong.
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.
A series across separate lots estimates a process. Repeat tests on one lot estimate the measurement. Both are useful and they answer different questions.
date of analysis matters as much as the number
That service reports area percent by default. Worth stating, since the thread has been comparing it to a mass figure.
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.
If the report gives a mass spectrum as well as UV purity, say so.
Agreed — and two services on one batch is the strongest thing any of us can produce individually.
Correcting myself: I quoted net peptide content against somebody else’s area percent. Not a comparison.
Kept every report as a PDF with the batch in the filename. Two years in, it is the most useful folder I own.
post the claim next to the result or the number floats
Push back: three tests on one lot is one lot. It tells you about that lot and almost nothing about the next one.
Split one vial between Medutest and VendorInvestigate. The two numbers were within half a point of each other and I stopped worrying about which lab to trust.
Batch number and date of analysis?
First result I ever posted here got asked for the batch number and the claim. Fair, and my posts have been better ever since.
Area percent and net peptide content are different measurements and most reports give one. Quote which, or the comparison downstream is meaningless.
results without method are gossip with decimals
say whether you paid for it yourself
Disagree that this is a discrepancy. 99.6% against a claimed 99.0% is inside ordinary inter-lab variance in either direction.
Do you have the trace, or only the summary?
How many separate lots does your series cover?
SGN BPC, batch matched the paperwork, Medutest came back 99.6% against a claimed 99.0%. 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…8 comments in this branch · started by u/kenji_kimani
- 2First result I ever posted here got asked for the batch number and the…8 comments in this branch · started by u/noor_cardoso