chromatogram: the version I wish someone had shown me in week 1
Right, the purity question again, but with numbers this time.
I have 12 data points over 32 weeks. The pattern is consistent enough that I do not think it is chance, and boring enough that nobody is going to screenshot it, which is usually a good sign.
The thing I would flag for anyone new: the effect I am describing showed up at week 93, not week 47. People give up long before the interesting part.
Interested in whether this matches other people's logs or whether I am an outlier.
best — the order this archive was captured in
Three years on this site and the questions have not changed at all. Which is depressing or reassuring depending on the day.
That is net peptide content, not purity. Different number, different meaning.
area% and mass% are not the same and this whole post conflates them
Gradient goblin mode: changed the solvent composition 19 times, finally got good resolution on a gradient peak.
Yeah, the chromatogram profile matters more than the headline number.
Tracking number removed. It identifies both ends of a shipment.
Tracking number removed.
Yes, exactly this, and it is the bit that took me 83 weeks to accept.
related substances are where the story lives, not the main peak
state the method: column, gradient, detection wavelength, injection volume
Respectfully this is a sample of one presented as a finding.
co-elution is real and purity is usually not enough to resolve it
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.
state the method: column, gradient, detection wavelength, injection volume
Disagree but this is the good kind of wrong — it is specific enough to be checked.
state the method: column, gradient, detection wavelength, injection volume
two labs, two different baselines, two different purity numbers, both honest
Slight fix: the number was 98.1, not 98.0. Decimal point, but a fairly consequential one.
This is the correct method framing. Column and gradient are load-bearing fields.
Ran the same vial on two columns, different purity, both right, different separation. Method matters more than equipment.
Not to be pedantic but LC-MS and LC-MS are being used interchangeably and they are not interchangeable in real life.
Ran the same vial on two columns, different purity, both right, different separation. Method matters more than equipment.
- 1Disagree but this is the good kind of wrong — it is specific enough to be…8 comments in this branch · started by u/hedda_ekstrom
- 2Tracking number removed. It identifies both ends of a shipment.6 comments in this branch · started by u/sig_figs_sam