Speciation analysis of iodate and iodide in high salt brine by high performance liquid chromatography and inductively coupled plasma mass spectrometry
A sensitive and interference-free iodine speciation analysis in high salt matrix is crucial either in the application of iodine ion-exchange adsorption removal or in brine chemical engineering industrial of caustic soda. In this work, the high performance liquid chromatography (HPLC) hyphenated with inductively coupled plasma mass spectrometry (ICP-MS) was investigated. Peak splitting under high salt matrix was found and solved by the new efficient mobile phase 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 proved, 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 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 determine rapidly and exactly the iodine species of iodide and iodate at trace level in high salt brine samples.