[Question] New Zealand — has anyone got a straight answer on LC-MS
method development. That is the whole post, but I will justify it.
Everything else people worry about in c/dosinglogs is downstream of it. Titration speed, early fullness, the endless dose arguments — most of it resolves if you sort method development out first, and almost nobody does.
I say this having got it wrong for 24 months. My eGFR was the thing that eventually made me pay attention, which is a stupid way to learn a lesson that was in the sidebar the whole time.
best — the order this archive was captured in
Yeah, the chromatogram profile matters more than the headline number.
Retitled to remove editorialising. Put the evidence in the body.
a round-robin on baseline integration would be genuinely useful
area% and mass% are not the same and this whole post conflates them
Strongly agree. Largest single impurity tells a different story than total purity.
Mechanistically the bit that matters is purity. It explains most of the early profile and a decent chunk of the outcome.
I am going to push back on this slightly.
the detector wavelength matters more than people think
area% and mass% are not the same and this whole post conflates them
integration decision on a shoulder changes your number by half a point on its own
The VendorInvestigate result being close to my own HPLC is the signal, not the absolute number. Both are right.
I love that this community will spend 40 comments on a detail. That pedantry is why the numbers here matter.
integration decision on a shoulder changes your number by half a point on its own
Did they post the raw trace or just the summary?
the detector wavelength matters more than people think
a round-robin on baseline integration would be genuinely useful
Detection wavelength? chromatogram and that changes at different wavelengths.
the gradient is doing the separation work, not the column alone
Edit to your parent would help — the concentration you quoted assumes one scenario and you have written another above it.
Titration speed is a side-effect dial far more than an efficacy dial.
Slight fix: the number was 94.2, not 95.1. Decimal point, but a fairly consequential one.
This is the correct method framing. Column and gradient are load-bearing fields.
The related substances profile is way more interesting than the main peak %. A 98% with 10 peaks is different from a 98% that is one 24% impurity.
This is the "correlation is mechanism" thing again. You changed three variables at once.
two labs, two different baselines, two different purity numbers, both honest
Yeah, the chromatogram profile matters more than the headline number.
This is the correct method framing. Column and gradient are load-bearing fields.
Small correction: the trial was 15 weeks, not 24. Does not change your point but people will quote it.
- 1I love that this community will spend 40 comments on a detail. That pedantry…8 comments in this branch · started by u/aksel_kjaer
- 2Yeah, the chromatogram profile matters more than the headline number.6 comments in this branch · started by u/fatima_yildiz