FLAVONOIDS. II. INVESTIGATION METHODS Flavonoids pigments exert a broad range of biological activities in both plants and animals. Natural polyphenols mainly occur as glycosilated molecules, usualy with a b-linked sugar. In this paper are cited several methods and techiques uses in flavonoid analysis. Chromatographic methods are usually cited techniques for quantifying flavonoids. HPLC methods utilizing UV detection system are commonly employed, as the conjugated p-systems of flavonoids afford good UV absorbtion. IR spectroscopy is useful to determine the functional groups attached to the basic structure of the flavonoid molecule and this is of value in the later interpretation of NMR scans. In order to determine that the isolated compounds are flavonoid pigments, the UV spectra (with and without adding the specific agents) are compared with literature data.