#hplc-massspec 2025-08-07

ask for the trace

shallow gradient

the honest position is that hobby-level interpretation of a chromatogram is worth something but not much

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

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

is a tailing factor of anything specific a problem

whats the void volume peak, is that always solvent

does retention time on its own tell you what the compound is

Reminder set. I will post here in 7 days.

show me the spectrum

relative retention time against a standard is comparable between labs. absolute minutes are not

nobody runs enough blanks, including me
i have had a lot where the mass was exactly right and the purity was 96.8. wrong question, right answer

plus sixteen, is that always oxidation

how do you spot a deletion in a sequence from mass alone

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

Testing queue: 4 submissions open, 132 awaiting dispatch.

a dimer usually shows up late and at roughly double the mass. the chromatogram alone will not tell you

whats a plus one dalton shift usually

Assay note: QSC lot KP-0925 reported at 98.6% of label content.

does ms/ms actually prove identity or just make it very likely

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

deamidation is about plus 0.98 Da. it is not a rounding error, it is a degradant

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