Ion chromatography coupled with optical emission spectrometry (IC-ICP-OES) methodology for the analysis of inositol phosphates in food and feed
Corinna Henninger, Tobias Stadelmann, Daniel Heid, Katrin Ochsenreither, Thomas Eisele
Abstract
This study presents the development of ion chromatography coupled with inductively coupled plasma optical emission spectrometry (IC-ICP-OES) for the simultaneous determination and quantification of inositol phosphates (InsP x ). Using a CarboPac PA100 column with a nitric acid-water gradient, 28 InsP x isomers (InsP 6 to InsP 2 ) were separated within 33 min. The method eliminates baseline drift and post-column derivatization thereby simplifying detection and quantification. It achieves low detection limits of 63 μg/L P across a range of 63–3200 μg/L P. Various extraction and sample preparation methods for food and feed matrices were tested, including acidic and alkaline agents, C 18 SPE and spin concentrators. The analysis shows intra-day and intra-laboratory reproducibility with deviations smaller than 1 % for standard solutions and under 4 % for feed samples (80 % recovery rate of phytate). This methodology is applicable to explore enzymatic degradation pathways and the analysis of InsP x in complex food and animal feed matrices. • Coupling of IC-ICP-OES for inositol phosphate quantitation. • Investigation of InsP x extraction procedure and analysis from food and feed matrices. • Comparison of enzymatic phytate degradation in buffered phytic acid solutions and feed matrices.