The speciation analysis of iodate and iodide in high salt brine by high performance liquid chromatography and inductively coupled plasma mass spectrometry

Abstract

A sensitive and interference-free iodine speciation analysis in high salt matrix is crucial either for the application of iodine ion-exchange adsorption removal or in chlor-alkali industrial of caustic soda. In this study, we investigated the iodine speciation using the high performance liquid chromatography (HPLC) coupled with inductively coupled plasma mass spectrometry (ICP-MS). Peak splitting under high salt matrix was found and solved using the new efficient mobile phase of ammonium carbonate. A high-efficiency separation anion-exchange column (Dionex IonPac AS-14) for iodate and iodide with 100 mM (NH₄)₂CO₃ solution at pH = 10 as mobile phase was confirmed, and the total running time of individual sample was within 8 min. Linear standard calibration plots were obtained in a concentration range of 1.0–100 μg L⁻¹ for both iodate and iodide, and the detection limits were 0.05 μg L⁻¹ for the former and 0.20 μg L⁻¹ for the latter. A precise analytical procedure of HPLC-ICP-MS was developed to rapidly and exactly determine the iodine species of iodide and iodate at trace levels in high salt brine samples.