three years of LC-MS threads, summarised so you do not have to read them
three years of LC-MS threads, summarised so you do not have to read them — a position I have arrived at slowly and would like tested.
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.
Chased a ghost peak for three weeks. It was the plumbing. It is always the plumbing.
Carryover from a previous high-concentration injection looks exactly like a small impurity. The blank injection is four minutes and it removes the ambiguity entirely.
Would rather be corrected in public than confident in private.
best — the order this archive was captured in
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.
Did you run a blank between injections?
Bought a second-hand instrument and learned more in six months of fixing it than in three years of reading traces.
How old is the column and roughly how many injections has it seen?
Not convinced by that integration. Dropping the baseline there absorbs part of the shoulder into the main peak.
Retention time shifted 0.4 minutes and I assumed the worst. It was the column temperature.
Yes — system suitability first. Without it the number is an assertion about the instrument, not the sample.
Is that baseline drawn by the software or by hand?
- 1Mass spectrometry answers identity. UV purity answers relative quantity…9 comments in this branch · started by u/hugo_bergstrom