Determination of Isomers of Inositol Mono- to Hexaphosphates in Selected Foods and Intestinal Contents Using High-Performance Ion Chromatography

Abstract

A sensitive high-performance ion chromatography (HPIC) method for separation and quantitative determination of inositol mono- to hexaphosphate (IP1−IP6) isomers in selected foods and intestinal contents is described. The method includes extraction of samples with HCl, separation of the inositol phosphates from the crude extract by anion-exchange chromatography, separation on high-performance ion-exchange columns with gradient elution in two combined HPIC systems, and detection using either postcolumn reaction and UV detection (system 1) or chemically suppressed conductivity detection (system 2). IP2−IP6 in samples were determined on the first system, which also separated isomers of IP4 and IP5. Fractions of IP1−IP3 from the first system were transferred to the second system after some additional sample preparation and analyzed for isomers. The applicability and sensitivity of the method are illustrated by measuring the content of inositol phosphates in foods, ileal contents, and feces of human balances. Keywords: Inositol phosphate isomers; high-performance ion chromatography; HPIC; food; intestinal content