how much of what we believe about purity actually comes from below spec threads
Genuine question, and the title is the question: how much of what we believe about purity actually comes from below spec threads. A series across separate lots estimates a process. Repeat tests on one lot estimate the measurement. Both are useful and they answer different questions. Inter-lab variance on this assay…
Fourth lot from the same supplier in the log now and the band has been tight the whole way. That consistency is the actual finding.
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.
Do you have the trace, or only the summary?
a result with no batch number is about a vial nobody can identify
a result with no batch number is about a vial nobody can identify
crp_curious is right that the band matters more than the peak. Consistency across lots is the finding.
if you are going to test, test the thing you actually received
Disagree that this is a discrepancy. 97.5% against a claimed 97.0% is inside ordinary inter-lab variance in either direction.