Determination of free myo-inositol in milk and infant formula by high-performance liquid chromatography.

A high-performance liquid chromatographic method is described for the determination of supplemental myo-inositol in infant formulas based on cows' milk. The technique incorporates pre-column derivatization with phenylisocyanate followed by reversed-phase gradient chromatography and ultraviolet detection. The protocol was also applied to a survey of free inositol at endogenous levels in the milk of cows, goats and humans. Nutritional preparations containing inositol at pharmacological levels are also amenable to a simplified isocratic analysis.