Analysis of element species fractions in buckwheat and amaranth flours by SEC/ICP-MS and MALDI-MS |
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Authors: | Oto Mestek Jan Polák Richard Koplík Jana Komínková Jiří Šantrůček Milan Kodíček František Kvasnička |
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Affiliation: | (1) Institute of Chemical Technology, Technicka 5, 166 28 Prague 6, Czech Republic |
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Abstract: | Fractionation of Co, Cu, Fe, Mn, Mo, Ni, P and Zn in extracts of buckwheat and amaranth flour in 0.02 mol·l−1 Tris-HCl (pH = 7.5) buffer was performed by SEC/ICP-MS. All metals except for Fe and Mn (both samples) and Cu (amaranth only) are concentrated in a low-molecular fraction (M r < 2 kDa). Fe is bound in a high-molecular fraction (M r > 150 kDa). The main part of Mn is present as a labile complex or an ionic form. Cu in amaranth extract is also bound in medium-molecular fractions (10 and 40 kDa) and in a high-molecular one (M r > 150 kDa). Fractions rich in trace metals were isolated using preparative-scale SEC and the organic ligands of metals were refined by immobilized metal affinity chromatography. Low content of sulphur-containing amino acids (Cys, Met) and high content of acidic amino acids (Glu, Asp) are typical for all these purified fractions. A part of Zn (buckwheat) and almost all Cu (amaranth) in the low-molecular fractions were located in phosphorus rich sub-fractions. However, all Ni (both samples), the majority of Zn (buckwheat) and all Cu (buckwheat) were found in phosphorus-less sub-fractions. No phytochelatins were found in MALDI-MS spectra of isolated ligands. |
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Keywords: | Amaranth Buckwheat Speciation Trace elements MALDI-MS ICP-MS |
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