Identification and characterization of selenium species in enriched green onion (Allium fistulosum) by HPLC-ICP-MS and ESI-ITMS
Monika Shah, Sasi S. Kannamkumarath, Jorgelina C. A. de Wuilloud, Rodolfo G. Wuilloud, Joseph A. Caruso
Journal of Analytical Atomic Spectrometry
Abstract
In this study speciation of selenium in selenium-enriched green onions (Allium fistulosum) was done with reversed-phase ion-pairing high performance liquid chromatography (RP-IP-HPLC) and size-exclusion chromatography (SEC) coupled on-line to ICP-MS for selenium specific detection. The plant extract obtained using sodium hydroxide (0.1 mol l−1) analyzed by SEC (CAPS 10 mmol l−1, pH 10.0) with ICP-MS detection showed the incorporation of selenium in both high (∼12 kDa) and low molecular weight (0.36–2 kDa) fractions. Presumably protein bound selenoamino acids were released using enzymes (Proteinase K and Protease XIV) and selenoamino acids found in cytosol in their free form were extracted using 0.1 M HCl. The extracts were analyzed for speciation studies by RP-IP-HPLC [0.1% (v/v) heptafluorobutyric acid, 5% (v/v) methanol, pH 2.5]. Matching the chromatographic retention times with commercially available standards provided evidence for the presence of Se-cystine, methylselenocysteine, Se-methionine, and inorganic selenium. Electrospray ionization ion trap mass spectrometry (ESI-ITMS) confirmed the presence of γ-glutamyl-Se-methylselenocysteine in green onions as has been reported in other onion types.
Extracted Claims
6 claims extracted from this paper into the knowledge graph
γ-glutamyl-Se-methylselenocysteine present in green onions (Allium fistulosum)
“Electrospray ionization ion trap mass spectrometry (ESI-ITMS) confirmed the presence of γ-glutamyl-Se-methylselenocysteine in green onions as has been reported in other onion types.”
inorganic selenium present in green onions (Allium fistulosum)
“Matching the chromatographic retention times with commercially available standards provided evidence for the presence of Se-cystine, methylselenocysteine, Se-methionine, and inorganic selenium.”
Se-methionine present in green onions (Allium fistulosum)
“Matching the chromatographic retention times with commercially available standards provided evidence for the presence of Se-cystine, methylselenocysteine, Se-methionine, and inorganic selenium.”