Page 3 of 21 · 503 questions tagged hplc.
I split one vial and sent halves to two independent laboratories. Purity came back 98.1% and 99.4%. Both sent chromatograms. Both look competent. The 1.3-point gap is…
Stated plainly: 96.4% · batch certificate. I have read the primary source rather than the summary, which has left me with more questions. I understand the headline. I…
Setup, so nobody has to ask: Janoshik · 97.6%. I noticed this today and I have not touched anything since, in case the state is diagnostic. I have not discarded…
Setup, so nobody has to ask: aggregation · cagrilintide · 25 °C. I keep seeing this stated as a fact with no explanation attached, and unexplained facts make me…
The case in front of me: survodutide · 97.9%. Please show the division. I want to check my own against yours. I would like the general form as well as the specific…
Setup, so nobody has to ask: Janoshik · 99.1%. I noticed this today and I have not touched anything since, in case the state is diagnostic. I have not discarded…
The particulars: VendorInvestigate · 97.6%. An unexpected observation, and I would like a differential rather than reassurance. The conditions were within what I…
What I am working with: TFC · an HPLC purity test. I want the working, not the result — I need to be able to redo it with different numbers. I care about the…
Concretely: semaglutide · a C4 column · liraglutide. These are treated as interchangeable and I do not think they are. If both are acceptable I would like to know…
The specifics, since they change the answer: deamidation · ecnoglutide · 40 °C. I would like the mechanism, because I want to be able to reason about the cases nobody…
Conditions: 98.8% · a C4 column · dulaglutide. I would like to know the limits of what can be inferred from this. What I am trying to avoid is over-reading a single…
Concretely: aspartimide formation · 40 °C. I want to know whether this is a real physical effect or an artefact of how it is measured. What prompted the question is…
Setup, so nobody has to ask: a formic acid mobile phase · cagrilintide · a wide-pore C18 column. The empirical answer seems settled. The explanation does not. If the…
I sent two vials from two different batches, both labelled 10 mg semaglutide, for independent testing and asked for purity and quantification on each. The results…
Details up front: Medutest · 98.4%. Before I write this off, I want to check whether it is a known failure mode. I have the lot number, the certificate and the date,…
What I am working with: dimerisation · a GLP-1 receptor agonist · 2–8 °C. The empirical answer seems settled. The explanation does not. If the honest answer is that…
The specifics, since they change the answer: VendorInvestigate · 95.2%. Something has gone wrong and I would like to know how badly before I decide what to do.…
Conditions: 97.6% · date of analysis. I would like to know the limits of what can be inferred from this. What I am trying to avoid is over-reading a single result,…
What I have: 97.1% · retatrutide. This should be a straightforward calculation and I keep getting two different answers. The numbers are arbitrary; the method is what…
Conditions: ecnoglutide · 99.1%. I want the working, not the result — I need to be able to redo it with different numbers. I care about the precision as well as the…
The particulars: 99.1% · chromatogram. I want to understand what this actually establishes, as opposed to what it is being used to imply. My concern is that I am…
Details up front: a GLP-1 receptor agonist · Janoshik. I can parse the result. I am less sure what it licenses me to conclude. I have deliberately not looked at…
Details up front: 96.8% · a C8 column · liraglutide. This is presented as though it settles something, and I am not convinced it does. I have two documents that…
What I am working with: dimerisation · a GLP-1 receptor agonist · 37 °C. The empirical answer seems settled. The explanation does not. If the honest answer is that…