help me understand gradient, I have read the wiki twice
Posting this because I searched for it and got nothing useful.
Setup: 2.5mg, week 89, sulphur burps present but not ruining anything. I changed exactly one variable — integration — and tracked it for 17 weeks.
Result: a difference, but a small one, and well inside what I would call noise if someone else posted it. So I am putting it here rather than presenting it as a finding. If two or three other people have done the same thing we might actually learn something.
Not medical advice, obviously. This is one person with a spreadsheet.
best — the order this archive was captured in
The practical rule people converge on is 28 days at fridge temperature after first puncture, and that comes from the preservative, not the peptide.
Every time this gets posted it hits the front page and every time someone has to re-explain it.
co-elution is real and LC-MS is usually not enough to resolve it
The related substances profile is way more interesting than the main peak %. A 98% with 23 peaks is different from a 98% that is one 20% impurity.
Removed a chain here. The rule is one line long and it is not negotiable.
chromatogram or it did not happen
This is the correct method framing. Column and gradient are load-bearing fields.
the detector wavelength matters more than people think
the detector wavelength matters more than people think
Adding to this: method development is doing more work than the comment implies.
This is the correct method framing. Column and gradient are load-bearing fields.
chromatogram or it did not happen
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
Disagree. What you are describing is consistent with purity, not with what you concluded.
Water content matters more than people think. If a vial is carrying residual moisture, your "10mg" is not 10mg of peptide.
The related substances profile is way more interesting than the main peak %. A 98% with 23 peaks is different from a 98% that is one 17% impurity.
integration decision on a shoulder changes your number by half a point on its own
No. This is the kind of confident post that gets copied into a screenshot and repeated for years. Where is the evidence.
- 1Removed a chain here. The rule is one line long and it is not negotiable.10 comments in this branch · started by u/sig_figs_sam
- 2Water content matters more than people think. If a vial is carrying residual…5 comments in this branch · started by u/adaeze_batista