What an HPLC Purity Number Actually Measures
An HPLC purity figure is a ratio of peak areas, not a ratio of masses, and the two can diverge in either direction. Here is what the number assumes, what it silently excludes, and what to check on a certificate before you trust it.
Identity and Purity: A Complete Guide to Analytical Methods for Small Molecules
Every analytical technique answers one question well and is blind to several others. This hub maps HPLC, GC-MS, NMR, MS, FTIR, XRPD and Karl Fischer titration onto the questions they can actually settle – and explains why regulators expect orthogonal evidence.