TRT
New Member
I am sorry to say this but there is no mention about Amino Acid Analysis in the Somatropin part of USP. Where did you get this information?
MW difference 100 Da can not be overlooked in any way by mass spectrometer. Usual accuracy is somewhere between 1 and 0.001 Da, depending on particular instrument.
The two science nerds going at it. I love it, don't understand much of it but I love it! LolA MS assay is the average MW of those compounds with a sample and IF the MW mean variance is close enough together a change as in deletion of one amino acid can readily be "missed".
For instance a variance of 0.01 to 0.001 for a sample with a MW of 22KD speaks to the issue directly bc in this instance such a variance equals 22 to 220 daltons.
Stated another way bc MS is an average MW of those compounds within a particular peak it lacks the specificity of an AAA.
The answer to your USP question is based on research conducted at the outset of RHGH development and testing for QC which became the eventual USP standard.