A rapid and sensitive high-performance ion chromatography method for separation and quantitative determination of inositol mono- and diphosphate (IP 1-IP 2) isomers using pulsed amperometric detection is described. The method involves extraction of samples with HCl, separation of inositol phosphates from the crude extract by anion-exchange chromatography, NaAc gradient elution in an NaOH environment to perform isomer separation on a high-performance anion-exchange column, and detection with pulsed amperometric detector. The applicability and sensitivity of the method is illustrated by measurement of the content of IP 1 and IP 2 in foods, human ileal contents, and enzymatic hydrolysis products of phytate (inositol hexaphosphate). The major IP 1 and IP 2 isomers formed 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.