[Question] is 99.0% actually fine or am I being sold a rounding error
The claim in the title is exactly the claim I am making: is 99.0% actually fine or am I being sold a rounding error. Nothing implied beyond it. To save the first four comments: 99.0%. Sent one vial to Medutest and Janoshik. 98.4% and a claimed 97.5%. Cost me more than the vial and I would do it again. LC-MS gives you…
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.
Agreed — the itemised related substances table is the difference between a document and a receipt.
a certificate with no method line is decorative
That is the catalogue certificate rather than the batch-specific one. Same layout, completely different status.
chromatogram or it did not happen
HPLC-UV and LC-MS answer different questions
Correcting myself upthread: I said the date was missing and it is on the second page, which I had not scrolled to.
Correcting myself upthread: I said the date was missing and it is on the second page, which I had not scrolled to.
Disagree on this specific point. Two honest labs can resolve that impurity differently and report different numbers.
water content is on there and everyone skips it
Agreed on asking for the storage condition. It is one line and it changes how you read the entire stability claim.
UV at 214nm sees the peptide bond and picks up almost everything; at 280nm you are looking at aromatics only. Which wavelength the number came from is part of the number.