Synthesis of Colloidal (Mixed) Metal Pyrophosphate Salts

Abstract

Mineral deficiency is common worldwide and can lead to serious diseases in the long-term. To prevent such diseases, nutrition can be fortified with dietary minerals. Fortification with colloidal dispersions of water insoluble mineral compounds is an option for liquid products. Colloidal dispersions of (mixed) metal pyrophosphate salts were prepared by different re-precipitation methods: an intermediate was dissolved in HCl and the pH was raised in a controllable way. Stable dispersions of MgPPi, FeIIMgPPi, FeIIIMgPPi and ZnMgPPi were obtained by injection and it was found how the stability depends on a combination of particle size, surface charge and ionic strength of the dispersion medium. Characterization was performed by dynamic light scattering, transmission electron microscopy, energy dispersive X-ray spectroscopy and powder X- ray diffraction.