three years of HPLC threads, summarised so you do not have to read them
chromatogram. That is the whole post, but I will justify it.
Everything else people worry about in c/dosinglogs is downstream of it. Titration speed, reflux, the endless dose arguments — most of it resolves if you sort chromatogram out first, and almost nobody does.
I say this having got it wrong for 24 months. My ApoB 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
two labs, two different baselines, two different purity numbers, both honest
two labs, two different baselines, two different purity numbers, both honest
Yes, exactly this, and it is the bit that took me 79 weeks to accept.
Edit to your parent would help — the concentration you quoted assumes one scenario and you have written another above it.
Strongly agree. Largest single impurity tells a different story than total purity.
two labs, two different baselines, two different purity numbers, both honest
a round-robin on baseline integration would be genuinely useful
related substances are where the story lives, not the main peak
Yeah, the chromatogram profile matters more than the headline number.
Respectfully this is a sample of one presented as a finding.
co-elution is real and chromatogram is usually not enough to resolve it
related substances are where the story lives, not the main peak
Disagree on that part. 96.8% and 96.2% on the same vial is normal.
Not to be pedantic but chromatogram and method development are being used interchangeably and they are not interchangeable in real life.
The PeptideMeter result being close to my own HPLC is the signal, not the absolute number. Both are right.
the detector wavelength matters more than people think
state the method: column, gradient, detection wavelength, injection volume
This is the "correlation is mechanism" thing again. You changed three variables at once.
Gradient goblin mode: changed the solvent composition 19 times, finally got good resolution on a integration peak.
the detector wavelength matters more than people think
Yeah, the chromatogram profile matters more than the headline number.
the detector wavelength matters more than people think
state the method: column, gradient, detection wavelength, injection volume
area% and mass% are not the same and this whole post conflates them
Three years on this site and the questions have not changed at all. Which is depressing or reassuring depending on the day.
Ran the same vial on two columns, different purity, both right, different separation. Method matters more than equipment.
This is the correct method framing. Column and gradient are load-bearing fields.
This is the correct method framing.
Yes, exactly this, and it is the bit that took me 89 weeks to accept.
The related substances profile is way more interesting than the main peak %. A 98% with 4 peaks is different from a 98% that is one 8% impurity.
The related substances profile is way more interesting than the main peak %.
Disagree on that part. 99.1% and 99.2% on the same vial is normal.
- 1a round-robin on baseline integration would be genuinely useful9 comments in this branch · started by u/samir_falk
- 2state the method: column, gradient, detection wavelength, injection volume7 comments in this branch · started by u/cagrilintide_enthusiast