No you don't. No comparison against a "known pure sample" takes place whatsoever. HPLC is a process to separate the different components in a mixture and in a pure sample it will show a single spike in the chromatogram. NMR/MS are used to identity the component. MS for example gives you the molecular weight which can be compared to the one calculated from the molecular formula of the component.To use HPLC you need to compare it with a " patron Drug " . That is , a sample of a the know pure drug. Again, I highly doubt any USA lab have a patron of RU .
