For the separation of hydrolyzed phenolics, a ternary
solvent system with increasing hydrophobicity and
changing pH was used. The solvents were 50 mM
ammonium dihydrogen phosphate, pH 2.6 (solvent A),
0.2 mM ortho-phosphoric acid, pH 1.5 (solvent B) and
20% of solvent A in 80% acetonitrile (solvent C). The
solvent gradient elution program is described in detail in
HaÈ kkinen et al. (1998). It was modi®ed from the
method of Lamuela-Ravento s and Waterhouse (1994),
described originally for measurement of wine phenolics.
The ¯ow rate was 0.5 ml minÿ1 and injection volume
was 20 ml. Development and validation of the method
has been described in detail by HaÈ kkinen et al. (1998).