2.1 Chemicals
All chemicals, including Ferrous sulfate
(FeSO4.7H2O, Carlo Erba), sodium
hydroxide (NaOH, Carlo Erba), acetonitrile (Sigma-Aldrich),
2,4-dichlorophenoxyacetic acid (2,4-D, Sigma-Aldrich), hydrogen peroxide
(H2O2, Carlo Erba), Sodium fluoride
(NaF, Sigma-Aldrich), sodium bicarbonate (NaHCO3,Sigma-Aldrich) and Milli-Q water were used to perform all the
experiments. All the reagents were of analytic grade and used without
further purification.