#hplc-massspec 2025-02-07

Friday10 messages4 participantstimes are UTC

Highlights from this day

peak_split — i asked Medutest for the raw trace and they sent it. that is the right answer to that question 03:23
mag_citrate — if the number you are staring at is a third of what you expected, do the charge state arithmetic before you panic 03:43
charge_state — two labs a point or two apart on the same lot is normal and gets mistaken for one of them being wrong constantly 04:23
ms_ms_mira — a warm transit can put a visible degradant peak on a chromatogram. that is what 24 days at ambient does 04:25

i asked Medutest for the raw trace and they sent it. that is the right answer to that question

tirzepatide is about 4813.5 Da, so 2+ is near 2407.8 and 3+ near 1605.5

the first peak is the solvent. it is always the solvent

do the arithmetic

if the number you are staring at is a third of what you expected, do the charge state arithmetic before you panic

📉1

coming back after 15 months, what changed in how you read these

for the archive oxidation is about plus 15.99 Da and is usually methionine or tryptophan

two labs a point or two apart on the same lot is normal and gets mistaken for one of them being wrong constantly

a warm transit can put a visible degradant peak on a chromatogram. that is what 24 days at ambient does

thats co-elution