[PSA] chromatogram is not what most of this community thinks it is
Something I noticed reading old threads that I have not seen said out loud. The advice on HPLC in this community changed substantially around the start of last year, and nobody went back and updated the older posts. So depending on which thread the search engine hands you, you get two contradictory answers with the…
Yeah, the chromatogram profile matters more than the headline number.
This is the correct method framing. Column and gradient are load-bearing fields.
Slight fix: the number was 99.0, not 98.9. Decimal point, but a fairly consequential one.
Detection wavelength? integration and that changes at different wavelengths.
Inter-lab variance on this kind of assay is routinely 1–2 points. Different column, different gradient, different integration.
a round-robin on baseline integration would be genuinely useful
Inter-lab variance on this kind of assay is routinely 1–2 points.
Disagree on that part. 97.4% and 96.2% on the same vial is normal.
That is net peptide content, not purity. Different number, different meaning.