[Lab] split one vial across Janoshik and Medutest — 98.7% and 98.3%
Short version of the title, which is already short: split one vial across Janoshik and Medutest — 98.7% and 98.3%. Longer version underneath. Since the title puts numbers in the shop window: 98.7% and 98.3%. Bought a second-hand instrument and learned more in six months of fixing it than in three years of reading…
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.
What wavelength, and what was the gradient?
Correcting myself upthread: I said the gradient was linear and looking again it has a hold in the middle.
I would not blame the sample yet. Everything you have described is consistent with the column rather than the vial.
LC-MS for identity, UV for relative quantity
That figure cannot be quoted to two decimals off that baseline. The precision is not in the data.
That figure cannot be quoted to two decimals off that baseline.
rasmus_petrescu 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.
Same view — reporting the gradient is what makes a result checkable rather than merely stated.
Not convinced by that integration. Dropping the baseline there absorbs part of the shoulder into the main peak.