what would you tell week-1 you about LC-MS
Right, the purity question again, but with numbers this time.
I have 5 data points over 10 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 26, not week 75. 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
related substances are where the story lives, not the main peak
Did they post the raw trace or just the summary?
Removed a chain here. The rule is one line long and it is not negotiable.
I am going to push back on this slightly.
Crossposting this to c/glp1eu because the people who need it are not reading this community.
Small correction: the trial was 16 weeks, not 30. Does not change your point but people will quote it.
Detection wavelength? method development and that changes at different wavelengths.
Yeah, the chromatogram profile matters more than the headline number.
instrument quality is less important than analyst consistency
instrument quality is less important than analyst consistency
This is the correct method framing. Column and gradient are load-bearing fields.
Detection wavelength? gradient and that changes at different wavelengths.
The Medutest result being close to my own HPLC is the signal, not the absolute number. Both are right.
state the method: column, gradient, detection wavelength, injection volume
This is the correct method framing. Column and gradient are load-bearing fields.
a round-robin on baseline integration would be genuinely useful
Detection wavelength?
Adding to this: integration is doing more work than the comment implies.
co-elution is real and HPLC is usually not enough to resolve it
co-elution is real and HPLC is usually not enough to resolve it
Yes, exactly this, and it is the bit that took me 87 weeks to accept.
Detection wavelength? HPLC and that changes at different wavelengths.
state the method: column, gradient, detection wavelength, injection volume
related substances are where the story lives, not the main peak
Water content matters more than people think. If a vial is carrying residual moisture, your "10mg" is not 10mg of peptide.
Water content matters more than people think.
Adding to this: purity is doing more work than the comment implies.
area% and mass% are not the same and this whole post conflates them
Water content matters more than people think.
Yes, exactly this, and it is the bit that took me 12 weeks to accept.
Yeah, the chromatogram profile matters more than the headline number.
- 1Crossposting this to c/glp1eu because the people who need it are not reading…19 comments in this branch · started by u/zeynep_zielinski
- 2Water content matters more than people think. If a vial is carrying residual…4 comments in this branch · started by u/blunt_coldbox_2024