[Lab] 12th independent test on QST — 98.6% on a claimed 98.5%, and the trend is the interesting part
12th independent test on QST — 98.6% on a claimed 98.5%, and the trend is the interesting part. One vial, one service, one member paying, which is the only kind of result this board should treat as evidence. Hard numbers: 98.6% and 98.5%. Anything softer than that is flagged as an impression. My first certificate had…
Related substances itemised individually is a much stronger document than a single total, because it tells you the shape of the impurity profile rather than its size.
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.
Are the related substances itemised or is it a single total?
area% is not mass%, and the difference is the whole game
Asked Homopeptide for the batch-specific certificate and had the full document — batch, date, method line naming the column — inside six hours. That is now my baseline for everybody.
the related substances line is where the story is
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.
Does the lot on the vial match the lot on the page?
water content is on there and everyone skips it