ANALYSIS OF INOSITOL MONOPHOSPHATE AND DIPHOSPHATE ISOMERS USING HIGH-PERFORMANCE ION CHROMATOGRAPHY AND PULSED AMPEROMETRIC DETECTION

A rapid and sensitive high-performance ion chromatography method for s eparation and quantitative determination of inositol mono- and diphosp hate (IP1-IP2) isomers using pulsed amperometric detection is describe d. The method involves extraction of samples with HCl, separation of i nositol phosphates from the crude extract by anion-exchange chromatogr aphy, NaAc gradient elution in an NaOH environment to perform isomer s eparation on a high-performance anion-exchange column, and detection w ith pulsed amperometric detector. The applicability and sensitivity of the method is illustrated by measurement of the content of IP1 and IP 2 in foods, human ileal contents, and enzymatic hydrolysis products of phytate (inositol hexaphosphate). The major IP1 and IP2 isomers forme d during phytate hydrolysis with wheat phytase were shown to be Ins(2) P, DL-Ins(1)P, and DL-Ins(1,2)P-2 and with Aspergillus niger phytase, Ins(2)P and DL-Ins(1,2)P-2.