gradient

is 97.4% actually fine or am I being sold a rounding error. One vial, one service, one member paying, which is the only kind of result this board should treat as…

gradient — 17 things I got wrong before I got it right. I have gone back and forth on this for months. Gave the same trace to two people I trust and got two…

does HPLC actually matter or is it forum lore at this point. I am not trying to be the "source?" guy. I would just like a source. System suitability — repeat…

the gradient everyone uses for sema and why it under-resolves the des-amido. It comes up every few weeks and the answer has not changed. The system suitability…

how do you actually verify LC-MS — that is what I am asking, and I have already read the wiki twice. Reading a trace posted here, in the order I actually look at…

Genuine question, and the title is the question: genuine question about chromatogram that I am slightly embarrassed to ask. Sent the same vial to PeptideMeter and…

the chromatogram rule is doing its job and people should stop complaining. Short post, long comment section, probably. Homopeptide sent me the column, the gradient and…

Putting this to the board: proposal — a flair for gradient posts. A shoulder that does not baseline-resolve cannot be quantified honestly. You can report it as an…

Asking properly rather than in a comment on somebody else’s thread: does method development actually matter or is it forum lore at this point. Retention time shifted…

peak at 4.2 min, nobody can tell me what it is, ideas. Not a hot take, just something I have not seen said plainly here. Chased a ghost peak for three weeks. It was the…

Yes, probably, and this thread exists so I can link it instead of retyping it. Sources of legitimate disagreement on the same physical sample, roughly in order of how…

integration — what am I missing here — that is what I am asking, and I have already read the wiki twice. Mass spectrometry answers identity. UV purity answers relative…

two labs, same vial, 98.1 and 96.4. both right. I am not trying to be the "source?" guy. I would just like a source. Gave the same trace to two people I trust and got…

Two years ago I bought a decommissioned system for less than a decent bicycle. Since then I have learned more analytical chemistry than I ever wanted and spent more…

Question in the title, detail here: chromatogram — what am I missing here. Area percent is the integrated area of your peak over the total integrated area at one…

can we stop arguing about gradient until somebody posts a number. I would rather ask a basic question now than get this wrong quietly for two months. Chased a ghost…

retention time shifted 0.4 min and nobody wants to talk about it. I have gone back and forth on this for months. System suitability — repeat injections, tailing factor,…

Question in the title, detail here: someone explain gradient to me like I have not read a paper in years. WWB sent me the column, the gradient and the theoretical mass…

reading HPLC threads from 2024 and half of it aged badly. I have gone back and forth on this for months. System suitability — repeat injections, tailing factor, plate…

Question in the title, detail here: genuine question about purity that I am slightly embarrassed to ask. WWB sent me the column, the gradient and the theoretical mass…

the method development advice in here is 2 years out of date, and I am aware this is a minority view on this board. 2 years. Those are measured, not estimated, and not…

The title is the argument: reading integration threads from 2024 and half of it aged badly. Here is the rest of it. GGPeps sent me the column, the gradient and the…

Research peptide, not a GLP-1, from a vendor I will not name because this is a methodology question rather than a vendor post. MS confirms the expected molecular mass…

reading purity threads from 2024 and half of it aged badly — a position I have arrived at slowly and would like tested. A shoulder that does not baseline-resolve cannot…

why does nobody talk about HPLC. I am not trying to be the "source?" guy. I would just like a source. Why two honest labs report different numbers on the same vial.…