Identification and quantitation of seleno-amino acids in mung bean sprouts by high-performance liquid chromatography coupled with mass spectrometry (HPLC–MS)

Selenium (Se)-enriched mung bean sprouts were obtained by cultivating the sprouts in the presence of different concentrations of Se. The sprouts were dried and ground into a powder, which was then subjected to ultrasound-aided hot enzymatic hydrolysis achieved with trypsin and proteinase K. The hydrolyzed sample was then subjected to HPLC–MS analysis, which was developed to specifically identify the presence of seleno- l -methionine (Se-Met), methyl-seleno- l -cysteine (Se-MeSeCys) and L-selenocystine (Se-Cys) and quantitate their concentrations in the Se-enriched mung bean sprouts. Positive ion multiple reaction monitoring (MRM) was used to measure the seleno-amino acids in the samples. The results showed that Se-MeSeCys was the major seleno-amino acid in mung bean sprouts while Se-Met and Se-Cys were both minor species.