Abstract
In recent years high consumption of dietary supplements has been observed. However, the consumption of dietary supplements may lead to the unexpected side effects that can be related to the number of adulterated supplements quite often marketed. It has prompted the search for a fast and reliable method of identification of main active compounds in the supplements. In this study, the isoflavones present in the methanol extracts of dietary supplements for menopause symptoms were identified by using direct infusion electrospray ionization tandem mass spectrometry. The product ion spectra of [M-H](-) ions derived from the extracts matched very well those obtained for standard compounds. Daidzein, genistein, and glycitein were identified in the soy-based supplements, while daidzein, formononetin, and biochanin A were identified in the red clover-based ones. The respective [M+Na](+) ions were also detected; however, their product ion spectra did not allow isoflavone identification. It can be concluded that the main isoflavones present in the extracts of dietary supplements can be successfully and quickly identified by using the direct infusion electrospray ionization in negative ion mode, followed by the tandem mass spectrometry experiment.