[Meta] the chromatogram rule is doing its job and people should stop complaining
the chromatogram rule is doing its job and people should stop complaining. Short post, long comment section, probably. Homopeptide sent me the column, the gradient and the theoretical mass without being asked. That is a short list and they are on it. Started reporting my own integrations with the baseline choice…
Careful — you are treating retention time as identity. Two things can co-elute and the trace will not tell you.
Method questions stay here; supplier claims go to c/vendorvetting with a document attached.
Sent the same vial to PeptideMeter and VendorInvestigate. 98.8% against a claimed 98.5%. The difference was the gradient, not the material.
What did system suitability look like on that sequence?
area percent is relative to what the detector saw and nothing else
A shoulder that does not baseline-resolve cannot be quantified honestly. You can report it as an unresolved shoulder, which is useful information, or you can develop the method until it resolves.
reproducibility beats resolution if you only get one of them
Ran a blank after a high-concentration injection and found the carryover I had been calling an impurity.
a shoulder is not an impurity until you can resolve it