Chemicals. All chemicals were of analytical grade. Solvents for chromatography were of high-performance liquid chromatography (HPLC) and liquid chromatography−mass spectrometry (LC−MS) quality. Glucosinolate standards (glucoiberin, glucoraphanin, and glucoerucin) were purchased from Oskar Tropitzsch (Marktredwitz, Germany). Isothiocyanate standards (iberin, sulforaphane, and erucin)were obtained from LKT Laboratories (St. Paul, MN, U.S.A.).Standards were stored at −20 °C.