the COA thing finally clicked for me and I want to write it down
the COA thing finally clicked for me and I want to write it down. Making the case below, and I expect to lose some of it in the comments. My first certificate had a compound name, a percentage and a logo. I thought that was normal. It is not, and now I know what to ask for. Asked for the storage condition behind the…
LC-MS gives you identity; UV purity gives you a relative quantity. A document with the first and not the second, or the reverse, is answering half the question.
batch number, date of analysis, method, individual impurities — that is the minimum set
The document I was worried about turned out to be a re-issue with a later creation date. Asked, got the original, entirely ordinary.
Did you ask for the batch-specific document, or is this the catalogue one?
Spent four months confusing area% and mass% in every post I made here. One explainer thread and it clicked permanently.
Net peptide content is the fraction of the powder that is actually peptide once counterion, water and residual solvent are accounted for. A 99% pure acetate salt can still be about 85% peptide by mass.