reading area percent threads from 2024 and half of it aged badly
reading area percent threads from 2024 and half of it aged badly. I have gone back and forth on this for months. 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. Area percent is the peak area of…
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.
Reminder: a question about a document is not an accusation about a supplier, and posts that blur the two get retitled.
ask for the storage condition the stability statement was written against
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.
the counterion is part of the mass you paid for
post the whole document, not the headline number
Area percent or net peptide content? They answer different questions.
Area percent or net peptide content?
This is the sentence to take away. The rest of the thread is footnotes to it.
Correction: that is net peptide content, not purity. Different number, different meaning, and the document says so if you read the row label.
Agreed — the itemised related substances table is the difference between a document and a receipt.
Batch number and date of analysis, are both on there?