show me the spectrum
#hplc-massspec 2025-10-08
Wednesday18 messages5 participantstimes are UTC
Highlights from this day
- void_volume — baseline drift on a gradient is normal. baseline drift on an isocratic hold is your column 19:25
- void_volume — nobody runs enough blanks, including me monoisotopic and average diverge more the bigger the molecule. say which one you are quoting 19:57
- gradient_greg — for the archive tirzepatide is about 4813.5 Da, so 2+ is near 2407.8 and 3+ near 1605.5, for what its worth 21:32
- gradient_greg — co-elution is the failure mode that a beautiful single peak is most likely to be hiding 21:33
- deamidation — a warm transit can put a visible degradant peak on a chromatogram. that is what 22 days at ambient does 21:38
ask for the trace
for the archive does retention time on its own tell you what the compound is
i have a number at about a third of what i expected, is that a charge state
baseline drift on a gradient is normal. baseline drift on an isocratic hold is your column
why do two labs integrate the same peak differently
within inter-lab range
👍14
plus 16 is oxidation
nobody runs enough blanks, including me
monoisotopic and average diverge more the bigger the molecule. say which one you are quoting
thats co-elution
retention time is a hint
is monoisotopic or average mass the one on most certificates
shallow gradient
💀8😂7👀1
has anyone ever had a result where the mass was right and the purity was wrong
for the archive tirzepatide is about 4813.5 Da, so 2+ is near 2407.8 and 3+ near 1605.5, for what its worth
co-elution is the failure mode that a beautiful single peak is most likely to be hiding
🎉15
run a blank
peak RRT area% note
1 0.42 0.31 solvent front
2 0.88 0.44 related substance
3 1.00 98.72 main
4 1.14 0.53 related substancea warm transit can put a visible degradant peak on a chromatogram. that is what 22 days at ambient does