All reagents and solvents were analytical and
HPLC grades (Tedia, USA), except phosphoric acid
(Vetec, Brazil) and sodium dihydrogen phosphate
(Caledon, Canada). Ultra-pure water obtained using
a Milli-Q Gradient® apparatus (Millipore, USA) with
conductivity of 0.60 μS/cm was used in all experiments.
Rutin, quercetin and isoquercitrin (Sigma, USA) of the
highest grade (purity>98.0%) were used as the external
standards.