three years of certificate of analysis threads, summarised so you do not have to read them
Right, the purity question again, but with numbers this time.
I have 24 data points over 10 weeks. The pattern is consistent enough that I do not think it is chance, and boring enough that nobody is going to screenshot it, which is usually a good sign.
The thing I would flag for anyone new: the effect I am describing showed up at week 90, not week 44. People give up long before the interesting part.
Interested in whether this matches other people's logs or whether I am an outlier.
best — the order this archive was captured in
Did they give you the chromatogram or just the summary line?
the counterion is part of the mass you paid for
PDF metadata is checkable in fifteen seconds
PDF metadata is checkable in fifteen seconds
Counter-anecdote: opposite result, same dose. Which mostly tells us the variance is huge.
area% is not mass%, and here is exactly why it matters
The COA I was holding said 96.8% area and I thought it was trash. Turns out the method was solid and the impurity profile was clean.
Strongly agree. Mass% and area% are answering different questions on the same document.
Water content on the document? That affects your concentration math.
axis labels included, always
Are you looking at area% or net peptide content? Different numbers.
the method line is doing real work, not just window dressing
This is the correct framing. The COA structure matters as much as the number.
Tracking number removed. It identifies both ends of a shipment.
PDF metadata is checkable in fifteen seconds
area% is not mass%, and here is exactly why it matters
What is the method line say? Not the technique, the actual method.
chromatogram or it did not happen
Batch number and date of analysis? Both are load-bearing.
area% is not mass%, and here is exactly why it matters
Did they give you the chromatogram or just the summary line?
area% is not mass%, and here is exactly why it matters
area% is not mass%, and here is exactly why it matters
Yes, exactly this, and it is the bit that took me 53 weeks to accept.
purity and net content are two different numbers, same vial
no "is this good?" without saying what the compound and claimed purity are
area% is not mass%, and here is exactly why it matters
Batch number and date of analysis? Both are load-bearing.
chromatogram or it did not happen
Not to be pedantic but certificate of analysis and COA are being used interchangeably and they are not interchangeable in real life.
post the whole document, not the headline number
- 1Did they give you the chromatogram or just the summary line?9 comments in this branch · started by u/emil_agyeman
- 2PDF metadata is checkable in fifteen seconds5 comments in this branch · started by u/milos_vanhecke