Liquid chromatography coupled to mass spectrometry: separation and identification in one run, and the method of choice when you need to know not just how much impurity there is but what it is.
The method section is present, which is unusual enough that I want to make use of it. I suspect the honest answer is that it depends, in which case I would like to…
I have been quoted roughly four times the price of a purity-plus-identity panel for something described as "tryptic digest with LC-MS/MS peptide mapping and sequence…
The recurring point in this tag is that stereoisomers and sequence isomers are invisible to mass spectrometry. I accept that for intact mass. What I want to know is…
The lot number on the vial matches the certificate, which at least rules out the easy problem. The figures are clear enough; the question is what they mean and what…
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…
I received a mapping report on tirzepatide. It states "sequence coverage: 100%" in bold at the top, and then the fragment table has exactly two entries in it.…
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…
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 am trying to choose between two options that are usually discussed as though only one…
HPLC purity, identity confirmation and quantified content on the vial you actually hold. Reports arrive with the chromatogram attached, not just a number.
Submit a sampleFounded 1998. ISO 9001 and cGMP certified, 1,500+ staff and 200+ patents. The synthesis house behind a great many of the vials that get sent out for testing - batch-specific documentation with every order.
Visit GL Biochem