shallow gradients hide related substances behind the main peak. a steeper one separates and looks worse, honestly
[edited]#hplc-massspec 2025-09-07
Sunday19 messages4 participantstimes are UTC
Highlights from this day
- new_here_nat — shallow gradients hide related substances behind the main peak. a steeper one separates and looks worse, honestly 17:32
- mag_citrate — relative retention time against a standard is comparable between labs. absolute minutes are not 19:40
- mag_citrate — ok so why do two labs integrate the same peak differently 19:42
show me the spectrum
how do you tell co-elution from a clean single peak
a dimer usually shows up late and at roughly double the mass. the chromatogram alone will not tell you
quick one why does integration change the number so much
a certificate with a number and no chromatogram is asking you to trust the integration you cannot see
ms/ms sequencing is the only thing i would call identity. everything else is circumstantial
the first peak is the solvent. it is always the solvent, ill dig out the number
baseline is drifting badly, is that the column or the mobile phase
integration difference
whats a plus one dalton shift usually
is uv at 214 or 280 better for peptides
is a tailing factor of anything specific a problem
you need more sample for identity than for purity. plan for that when you post it
run a blank
plus 16 is oxidation
within inter-lab range
relative retention time against a standard is comparable between labs. absolute minutes are not
lot-log.csv
629 rows · not retained in the public archive
ok so why do two labs integrate the same peak differently
[edited]✅14