[Meta] proposal — a flair for gradient posts
Putting this to the board: proposal — a flair for gradient posts. 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. System suitability — repeat injections, tailing factor,…
Retitled: the original claimed a comparison the post does not actually make.
Reading a trace posted here, in the order I actually look at things.
Axes first — if the wavelength and the time axis are not labelled, I stop. Then the baseline: where has it been drawn, and does the drawing absorb anything. Then peak shape: fronting, tailing, a shoulder that never resolves. Then the blank, if one was run, for carryover.
Only after all of that do I look at the percentage, and by then I usually know how much weight it deserves. The number is the last thing on the page and the first thing everybody argues about, which is exactly backwards.
you cannot report to two decimals off that baseline
two labs, two gradients, two honest answers
Mass spectrometry answers identity. UV purity answers relative quantity under the run conditions. A document with one and not the other is answering half the question, and the half it answers should be stated.
That figure cannot be quoted to two decimals off that baseline. The precision is not in the data.
system suitability before you believe any number on the run
That figure cannot be quoted to two decimals off that baseline.
Adding one practical thing — run the blank. It answers this before anyone has to argue about it.