Iron(II) reactions with glycine – suitable biomineralization model?

Abstract

The reactions of Mohr’s salt with amino acid glycine in aqueous solution and aerobic conditions were studied and obtained samples consist of different compounds. The obtained products were characterized by elemental analysis, infrared spectroscopy and the iron determination also and exhibited very low organic matter content – the sum of N, C, H and S content less than 20 % and Fe content around 40 %. Prepared samples consist of iron(II) amino acid complex [Fe(glyH)(SO₄)]_n, known as iron food supplement (FeGS) as the only sulphur containing compound. Its content varies from 26 % up to 46 %. Ferrous glycinate was obtained in the samples collected initially after the reaction in very low content < 7 %. Iron(III) hydroxy-oxide FeO(OH) was obtained in the range 40 – 65 %. The FeO(OH) content increased with the decreasing FeGS content. Formation of inorganic FeO(OH) suggest the ongoing redox reaction under aerobic condition therefore, it is suggested as a biomineralization reaction model.