Distinction of metal species of phytate by solid-state spectroscopic techniques

Solid-state 31P nuclear magnetic resonance (NMR) and x-ray absorption near edge structure (XANES) spectroscopies have provided knowledge on metal speciation of inorganic P. No effort has been made, however, to accurately assign speciated metal phytates (inositol hexaphosphoric acid salts) using these advanced techniques. Phytate is a predominant form of organic P in animal manure, soil, and other organic substances as each year 51 million Mg of phytate are formed in crops and fruits globally. Currently, the interactions and fate of phytate in the environment are poorly understood. Here we show the solid-state spectral characteristics of six metal phytates. Both spectra were affected by the metal species of the phytates, as significant differences were observed in the shape and position of spectra among the metal phytates. Reference spectra of these pure metal phytate compounds may help in identifying metal species of phytate in environmental samples by these advanced spectroscopic technologies. © Soil Science Society of America.