#hplc-massspec 2025-07-06

Sunday19 messages6 participantstimes are UTC

Highlights from this day

assay_not_purity — a certificate with a number and no chromatogram is asking you to trust the integration you cannot see 21:13
ms_ms_mira — has anyone ever had a result where the mass was right and the purity was wrong 21:26
ms_ms_mira — a warm transit can put a visible degradant peak on a chromatogram. that is what 12 days at ambient does 21:38
karl_fischer — update from 21 months ago: switched to asking for the chromatogram rather than the number and it changed everything 21:54
LC_MS_Lena — while im here is there any point running a blank if the sample is the question 22:00

show me the spectrum

🧊12🎉11

integration difference

a certificate with a number and no chromatogram is asking you to trust the integration you cannot see

thats the solvent peak

nobody runs enough blanks, including me

retention time is a hint

ask for the trace

has anyone ever had a result where the mass was right and the purity was wrong

📈2💀2✅11

a warm transit can put a visible degradant peak on a chromatogram. that is what 12 days at ambient does

chromatogram-overlay.png

1240 × 720 · 827 KB · not retained in the public archive

👀6

baseline is drifting badly, is that the column or the mobile phase

update from 21 months ago: switched to asking for the chromatogram rather than the number and it changed everything

do the arithmetic

ms/ms or it isnt identity

while im here is there any point running a blank if the sample is the question

run a blank

how much sample does a lab actually need for identity as well as purity

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

my peak has a shoulder on it, what does that usually mean

*that should say weekly