Determination of myo-inositol and phytic acid by gas chromatography using scyllitol as internal standard

Abstract

A gas chromatographic procedure for the determination of myo-inositol and phytic acid in natural products using scyllitol as an internal standard is described. Myo-inositol was liberated from phospholipids and phytic acid by hydrolysis in 2 mol l–1 hydrochloric acid at 120 °C. It was then separated from ionic substances by passage over a mixed cation–anion-exchange resin. Both myo-inositol and the internal standard scyllitol were silylated to their respective hexa-O-trimethylsilyl ethers and separated by capillary gas chromatography. Recoveries of myo-inositol from a spiked fish oil and from a squid phospholipid ranged from 91 to 107% and those of phytic acid from spiked fish flour ranged from 90 to 99%. Examples of phytic acid determinations in various cereals and pet foods are presented.