reagent grade. Dried St. John’s wort was obtained from a local
market. Sodium fluoride (NaF) was purchased from La Chema, Czech Republic.
Aluminum nitrate nonahydrate (Al(NO3)3·9H2O) and ethylenediaminetetraacetic acid disodium salt dihydrate
(Na2EDTA) were purchased from Sigma-Aldrich. Methyl salicylate
(99.2% pure, 2-(HO)C6H4CO2CH3) was obtained from JQC (Huayin) Pharmaceutical Co., Ltd.,
and sodium acetate (CH3COONa), acetic acid (CH3COOH), ethanol, iron(III) nitrate nonahydrate (Fe(NO3)3·9H2O), iron(II) chloride tetrahydrate (FeCl2·4H2O), manganese(II) nitrate tetrahydrate
(Mn(NO3)2·4H2O), ammonium chloride
(NH4Cl), potassium nitrate (KNO3), calcium nitrate
tetrahydrate (Ca(NO3)2·4H2O),
magnesium nitrate hexahydrate (Mg(NO3)2·6H2O), sodium nitrate (NaNO3), sodium chloride (NaCl),
sodium bromide (NaBr), sodium sulfate (Na2SO4), and boric acid (H3BO3) were purchased from
Merck. Sodium phosphate monobasic (NaH2PO4)
was obtained from Riedel-de Haen.