gradient — 17 things I got wrong before I got it right
gradient — 17 things I got wrong before I got it right. I have gone back and forth on this for months. Gave the same trace to two people I trust and got two integrations about a point apart. That was the most educational afternoon I have had here. Carryover from a previous high-concentration injection looks exactly…
UV response is not uniform across species. At 214nm you are looking at the peptide bond, which is why it is the working wavelength for this class; at 280nm you only see tryptophan, tyrosine and phenylalanine.
Agreed, and it is why BCH printing the column and gradient on the certificate is genuinely useful rather than decorative.
Agreed, and it is why BCH printing the column and gradient on the certificate is genuinely useful rather than decorative.
hazard_ratio_hal is right — the integration choice is a decision and it should be stated alongside the result.
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.
Started reporting my own integrations with the baseline choice stated. Arguments in my threads dropped by about half.
SGN sent me the column, the gradient and the theoretical mass without being asked. That is a short list and they are on it.
I would not blame the sample yet. Everything you have described is consistent with the column rather than the vial.
you cannot report to two decimals off that baseline
That is area percent, not mass percent. The trace cannot give you the second one.
Retention time shifted 0.4 minutes and I assumed the worst. It was the column temperature.