Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Variations of the UV-spectra of a water-ethanol solution of quercetin during its slow stepwise titration by NaOH within pH range 2-10, followed by the acidification up to pH = 4; (a) – UV-spectrum of quercetin in ethanol solution; (b) – at рН = 2; (c) – at рН = 10; (d) – UV-spectrum of solution after acidification to рН = 4.
