integration — 22 things I got wrong before I got it right. It is the sort of thing everyone half-believes and nobody writes down. Resolution between two peaks depends…
c/hplc — hot, page 4
Positions 76–100 of 130.
three years of gradient threads, summarised so you do not have to read them, which sounds obvious until you try to state the evidence for it. Carryover from a previous…
genuine question about LC-MS that I am slightly embarrassed to ask. Searched first, found three threads that contradict each other, hence the post. Resolution between…
Title says it — is 99.2% actually fine or am I being sold a rounding error — so here is the boring supporting detail that makes it worth anything. The relevant figures…
Sigma-Aldrich — certified reference materials
Reference standards, analytical reagents and system-suitability material. If you are running your own method, start with a known.
Reference standardsthe LC-MS question that gets asked weekly, answered properly, which sounds obvious until you try to state the evidence for it. WWB sent me the column, the gradient and…
how do you actually verify HPLC. Searched first, found three threads that contradict each other, hence the post. Ran a blank after a high-concentration injection and…
Short version of the title, which is already short: WXT cagri — PeptideMeter came back 97.8% against a claimed 97.0%. Longer version underneath. Since the title puts…
is 98.1% actually fine or am I being sold a rounding error, and before anyone asks: same batch throughout, single submission, no cherry-picking between services. The…
chromatogram is doing more work than we give it credit for — a position I have arrived at slowly and would like tested. A shoulder that does not baseline-resolve cannot…
Short version of the title, which is already short: split one vial across Janoshik and Medutest — 98.7% and 98.3%. Longer version underneath. Since the title puts…
CPC cagri — Janoshik came back 98.1% against a claimed 97.5%. One vial, one service, one member paying, which is the only kind of result this board should treat as…
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…
Title says it — split one vial across PeptideMeter and VendorInvestigate — 96.8% and 99.1% — so here is the boring supporting detail that makes it worth anything. The…
Genuine question, and the title is the question: why does nobody talk about gradient. UV response is not uniform across species. At 214nm you are looking at the peptide…
unpopular opinion: most of what gets said here about integration is guesswork. Not a hot take, just something I have not seen said plainly here. Chased a ghost peak for…
Janoshik Analytical — independent HPLC & mass spec
Send the vial, get the number. Third-party purity and identity testing, results published to you regardless of what they say.
Test a vialSponsoredGL Biochem (Shanghai) Ltd. — the synthesis house
Est. 1998. ISO 9001 and cGMP, 1,500+ staff, 200+ patents. There is a fair chance the vial you are about to send for testing started here. Batch-specific COA as standard.
glbiochem.netthe 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…
LC-MS is doing more work than we give it credit for, and I am aware this is a minority view on this board. Why two honest labs report different numbers on the same…
The claim in the title is exactly the claim I am making: MKM cagri — Medutest came back 97.2% against a claimed 97.0%. Nothing implied beyond it. Since the title puts…
someone explain LC-MS to me like I have not read a paper in years. Searched first, found three threads that contradict each other, hence the post. Resolution between…
Question in the title, detail here: genuine question about HPLC that I am slightly embarrassed to ask. MKM sent me the column, the gradient and the theoretical mass…
the HPLC question that gets asked weekly, answered properly. It is the sort of thing everyone half-believes and nobody writes down. Ran a blank after a…
The title is the whole question — how much of what we believe about HPLC actually comes from method development threads — but here is why I am asking. KP sent me the…
method development — 10 things I got wrong before I got it right. Change my mind, genuinely — I have no stake in being right about this. Bought a second-hand instrument…
reading chromatogram threads from 2024 and half of it aged badly — a position I have arrived at slowly and would like tested. Retention time shifted 0.4 minutes and I…
does LC-MS 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. Gave the same trace to two people I…