Validation of Modified High-Performance Ion Chromatography Analytical Method for Inositol Phosphates in Soybeans

Phosphorus in the form of phytic acid or <i>myo</i>-inositol hexakisphosphate is not absorbable by animals, leading to decreased bioavailability of essential minerals such as iron, zinc, and calcium. This study aimed to develop and validate a simple and efficient method for measuring inositol phosphates in soybeans. The four types of inositol phosphates analyzed were D-<i>myo</i>-inositol-1,5,6-triphosphate, D-<i>myo</i>-inositol-1,4,5,6-tetraphosphate, D-<i>myo</i>-inositol-1,3,4,5,6-pentaphosphate, and D-<i>myo</i>-inositol-1,2,3,4,5,6-hexakisphosphate using high pressure ion chromatography. For method validation, we assessed specificity, linearity, limit of detection, limit of quantification, precision, and accuracy for the four inositol phosphate types. Calibration curves for each inositol phosphate indicated high linearity (<i>r</i> ²≥0.9999). The intra and interday precision of the assays ranged from 0.22% to 2.80% and 1.02% to 8.57%, respectively. Recoveries measured using the standard addition method in soybeans varied from 97.04% to 99.05%. Accordingly, the analytical method was validated for detecting inositol phosphates in soybeans. Our results provide data on the phytic acid content of wild type and gene-edited soybeans by measuring individual inositol phosphates, which is expected to aid in breeding soybeans with reduced phytic acid levels.