Page 2 of 3 · 52 questions tagged mass-spec.
I am comparing a supplier certificate against an independent result on the same lot. I would like help reading this properly rather than being told what conclusion to…
This is my second independent submission on material from the same supplier. I would rather understand the derivation than memorise the outcome. Two people I asked…
Numbers first: +2 · 4813.5 Da. This should be a straightforward calculation and I keep getting two different answers. The numbers are arbitrary; the method is what I…
Setup, so nobody has to ask: FGP · identity confirmation by mass spectrometry. I have worked this out and I would like someone to find the error, because I suspect…
The deconvolved mass spectrum on a tirzepatide report shows the expected 4813.5 peak plus three satellites I do not understand: one at 4795.5, one at 4814.5 that…
I have two third-party reports in front of me. Both say "identity confirmed by ESI-MS" and both include a spectrum, but the spectra look nothing like the single clean…
For reference: identity confirmation by mass spectrometry · survodutide. I am at the decision point and I would rather think it through than improvise. I would rather…
Conditions: identity confirmation by mass spectrometry · semaglutide. I am trying to choose between two options that are usually discussed as though only one exists.…
Setup, so nobody has to ask: +3 · 4813.5 Da. The units are where I keep going wrong, so please be explicit about them. I have sanity-checked the order of magnitude…
I have both a purity figure and a content figure, which is why the discrepancy is visible. I can predict the outcome but I cannot explain it, which means I will get…
Setup, so nobody has to ask: identity confirmation by mass spectrometry · survodutide. I am at the decision point and I would rather think it through than improvise.…
The case in front of me: an HPLC purity test · aggregation · oral semaglutide. I want to know what the trade-off actually is rather than which option is fashionable.…
Details up front: +2 · 4731.3 Da. This should be a straightforward calculation and I keep getting two different answers. The numbers are arbitrary; the method is what…
Setup, so nobody has to ask: +3 · 3751.0 Da. The units are where I keep going wrong, so please be explicit about them. I have sanity-checked the order of magnitude…
Numbers first: +2 · 3751.0 Da. This should be a straightforward calculation and I keep getting two different answers. The numbers are arbitrary; the method is what I…
Concretely: a quantified content assay · fibrillation · dulaglutide. These are treated as interchangeable and I do not think they are. If both are acceptable I would…
Stated plainly: identity confirmation by mass spectrometry · survodutide. I am trying to choose between two options that are usually discussed as though only one…
Concretely: WXT · identity confirmation by mass spectrometry. I have worked this out and I would like someone to find the error, because I suspect there is one. My…
I have the report as a PDF with the chromatogram on page two, so I can quote specifics. The comparison I want does not seem to exist anywhere in a form I can…
This is my second independent submission on material from the same supplier. I am trying to choose between two options that are usually discussed as though only one…
Concretely: +5 · 4731.3 Da. Please show the division. I want to check my own against yours. I would like the general form as well as the specific number, so I can…
Setup, so nobody has to ask: +3 · 4207.2 Da. The units are where I keep going wrong, so please be explicit about them. I have sanity-checked the order of magnitude…
The particulars: +4 · 4113.6 Da. I would like the arithmetic checked rather than the conclusion asserted. I have deliberately not used an online calculator because I…
The specifics, since they change the answer: +4 · 4813.5 Da. I would rather understand the derivation than memorise the outcome. Two people I asked gave two answers…