Mössbauer and thermogravimetric study of ferrous gluconate

Ferrous gluconate Fe(C6H11O7)2·2H2O was investigated by means of57Fe (14.4 keV)-Mossbauer spectroscopy and thermogravimetry. The Mossbauer study was performed in the temperature range 80 to 423 K. It was found that Fe2+ occupies two distinctly different Mossbauer sites in the hydrated phase and a single site in the product of the thermal treatment. All samples were contaminated by some amount of Fe3+. A significant oxidation occurs during thermal treatment (about 378 K) at least for the samples exposed to the air. No Goldanskii-Karyagin effect has been detected, in contrast to the previous claim. It has to be noted that the ferrous gluconate is often used as the iron containing component of drugs used in the treatment of anaemia.