am I the only one who found integration harder than the injections
Long-ish post, sorry. tl;dr at the bottom.
I have been tracking LC-MS against ApoB for 17 weeks because I could not find anyone who had. The correlation is weaker than I expected, which is itself mildly interesting given how confidently people link the two in here.
Caveats up front: one person, one lab, one assay, no control, and I changed my training in the middle of it, which was stupid.
tl;dr: probably real, definitely smaller than the threads imply, and not worth reorganising your week around.
best — the order this archive was captured in
Did they post the raw trace or just the summary?
integration decision on a shoulder changes your number by half a point on its own
integration decision on a shoulder changes your number by half a point on its own
Disagree on that part. 99.2% and 99.3% on the same vial is normal.
state the method: column, gradient, detection wavelength, injection volume
Retitled to remove editorialising. Put the evidence in the body.
A shoulder on the main peak that 2 analysts integrated 23 different ways. Same trace, 97.6 spread.
Yeah, the chromatogram profile matters more than the headline number.
a round-robin on baseline integration would be genuinely useful
related substances are where the story lives, not the main peak
Strongly agree. Largest single impurity tells a different story than total purity.
the gradient is doing the separation work, not the column alone
I am going to push back on this slightly.
instrument quality is less important than analyst consistency
the detector wavelength matters more than people think
the gradient is doing the separation work, not the column alone
Ran the same vial on two columns, different purity, both right, different separation. Method matters more than equipment.
state the method: column, gradient, detection wavelength, injection volume
area% and mass% are not the same and this whole post conflates them
related substances are where the story lives, not the main peak
related substances are where the story lives, not the main peak
Counter-anecdote: opposite result, same dose. Which mostly tells us the variance is huge.
related substances are where the story lives, not the main peak
The practical rule people converge on is 28 days at fridge temperature after first puncture, and that comes from the preservative, not the peptide.
Rodent data is rodent data. Dose scaling is not linear and the models tell you what to investigate, not what to expect.
Yeah, the chromatogram profile matters more than the headline number.
Did they post the raw trace or just the summary?
- 1Retitled to remove editorialising. Put the evidence in the body.16 comments in this branch · started by u/peak_area_pete
- 2Did they post the raw trace or just the summary?5 comments in this branch · started by u/isabela_nilsen