As well, minute amounts of certain compounds may be
neglected because of their weak signals in the UV spectra.
Sephadex LH-20 column chromatography was performed to separate the crude methanol extract of rapeseed into different fractions that could be further analyzed by HPLC-PDA−ESI(−)-MSn (LCQ) and HPLC-DAD−ESI(−)-HRMS (QTOF),thereby allowing comprehensive and detailed characterization of the crude extract. Although some of the compounds may be dehydrated during subsequent concentration, no adverse effects on their identification were noted