purity — 6 things I got wrong before I got it right
Something I keep coming back to: purity — 6 things I got wrong before I got it right. 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. How to ask for a batch record without it turning into a negotiation. One email, three requests:…
Your name and address edited out of the screenshot above. The batch details are untouched and should stay.
The PDF creation date being later than the analysis date is usually a re-issue or a re-export. It is worth one question and it is not evidence of anything on its own.
a certificate with no method line is decorative
Asked for the storage condition behind the stability statement. Got it in a sentence. It is a two-line email and almost nobody sends it.
HPLC-UV and LC-MS answer different questions
water content is on there and everyone skips it
Sent one vial to Medutest and PeptideMeter. 98.3% and a claimed 98.0%. Cost me more than the vial and I would do it again.
Does the lot on the vial match the lot on the page?
Agreed on asking for the storage condition. It is one line and it changes how you read the entire stability claim.
net peptide content and purity are two different numbers on the same vial
Yes. The structure of the document matters at least as much as the number printed on it.