Selenium species in leaves of chicory, dandelion, lamb's lettuce and parsley

Lamb's lettuce, dandelion, parsley and four cultivars of chicory were cultivated aeroponically for 41 days with nutrient solution containing 7 mg Se/L in the form of Na2SeO4. Se compounds were determined by high performance liquid chromatography-ultraviolet treatment-hydride generation atomic fluorescence spectrometry (HPLC-UV-HG-AFS) in the green parts of the selected plants. Se species were extracted by water and by enzymatic hydrolysis with Protease XIV. Separation of Se-IV, Se-IV, SeMet, SeMeSeCys and SeCys(2) was made by a combination of anion and cation exchange chromatography in which the columns were connected on-line to a UV-HG-AFS detection system. Se accumulated efficiently in plant leaves up to 480 mu g/g dry mass, mostly as Se-IV, i.e. the form of Se in the nutrient solution. Beside inorganic Se, selenomethionine (6-21%), selenomethylselenocysteine (0.5-4.4%) and selenocistine (<DL-0.8%) were determined in the extracts after enzymatic hydrolysis. Some unidentified peaks were also observed in the chromatograms. (C) 2007 Elsevier Ltd. All rights reserved.