three years of related substances threads, summarised so you do not have to read them
three years of related substances threads, summarised so you do not have to read them, and I am aware this is a minority view on this board. 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. LC-MS…
a certificate with no method line is decorative
Area percent is the peak area of your compound over the total integrated area, at one wavelength, on one gradient. It is a relative measure of what the detector saw, not a mass fraction of the vial.
post the whole document, not the headline number
a total of 0.4% tells you less than four named impurities adding to 0.6%
a total of 0.4% tells you less than four named impurities adding to 0.6%
Disagree on this specific point. Two honest labs can resolve that impurity differently and report different numbers.
batch number, date of analysis, method, individual impurities — that is the minimum set
identity and quantity are two questions and most documents answer one