[Discussion] we are measuring HPLC at the wrong time and calling it noise
The title is the argument: we are measuring HPLC at the wrong time and calling it noise. Here is the rest of it. Area percent is the integrated area of your peak over the total integrated area at one wavelength on one gradient. Change any of those and the number changes without the sample changing. Reading a trace…
axis labels or the trace is decoration
Trace posted without axis labels — asked for a relabelled version rather than removing it.
Trace posted without axis labels — asked for a relabelled version rather than removing it.
Adding one practical thing — run the blank. It answers this before anyone has to argue about it.
Small fix — 214nm, not 210. It matters for the comparison you are making with the other run.
the column has a history and it shows in the peak shape
Sent the same vial to PeptideMeter and VendorInvestigate. 98.1% against a claimed 98.0%. The difference was the gradient, not the material.
LC-MS for identity, UV for relative quantity
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.