Rapid and accurate phytate quantification in plant tissues and grains via ion chromatography: Validation and application

Phytate (salts of myo-inositol hexakisphosphate) represents 65–90 % of total phosphorus in the grains, yet its accurate quantification in plant samples remains challenging. In this study, a novel ion chromatography method coupled with suppressed conductivity detection (IC−SCD) was developed for rapid and accurrate phytate determination in 15 plant samples. These included two model plants (N. tabacum and A. thaliana), four crop plants (O. sativa, B. rapa, S. lycopersicum, and T. aestivum), four fern plants (P. ensiformis, P. vittata, P. multifida, and P. cretica), and five grain samples (maize, rice, barley, oat, and wheat). The IC−SCD method achieved a low detection limit of 0.2 mg/L (0.04 mg/g) and enabled effective phytate separation from interferences of inositol trisphosphate and common organic acids, including malate, tartrate, oxalate, and citrate, which are inadequately resolved by high-performance liquid chromatography. Compared with the Wade method, which determines phytate by spectrophotometric measurement of absorbance after reaction with ferric chloride and sulfosalicylic acid, the phytate contents determined by IC−SCD were comparable in 5 grain samples (1.64−3.11 mg/g). However, much lower and more accurate values were obtained in 10 plant tissues (0.20−1.14 vs. 6.67−8.01 mg/g), with P. vittata showing the highest phytate content. The data indicate that Wade method overestimates phytate in plant tissues due to interference from organic acidss. This study demonstrates that the IC−SCD method provides a reliable and cost-effective analytical approach for rapid and accurate phytate determination, supporting improved evaluation of phosphorus dynamics in plant and feed research.