Imidazolium ionic liquids as mobile phase additives in reversed phase liquid chromatography for the determination of iodide and iodate.

An analytical method for the simultaneous determination of iodide and iodate by reversed phase liquid chromatography with ultraviolet detection using imidazolium ionic liquids as mobile phase additives was developed in this paper. Imidazolium ionic liquids, pyridinium ionic liquids, and common ion pair reagent tetrabutylammonium hydroxide as mobile phase additives were compared. The results indicated that imidazolium ionic liquids as the mobile phase additives were better than any tetrabutylammonium hydroxide or pyridinium ionic liquids. The relevant mechanisms of separation and detection for the anions were discussed. Imidazolium ionic liquids acted as ion pair reagents and ultraviolet absorption reagents in the separation and detection of the anions. The optimized mobile phase of methanol/0.3 mmol/L 1-hexyl-3-methylimidazolium tetrafluoroborate aqueous solutions (12/88, v/v), detection wavelength of 210 nm, and column temperature of 35 °C were used for the determination of iodide and iodate. Under these conditions, the detection limits of iodide and iodate were 0.02 and 0.03 mg/L, respectively. To evaluate the practicability of the method, the determination of iodide and iodate in medicines and beverages was performed by this method. The results are that the spiked recoveries were greater than 95% and RSD was less than 3.0%. The method was simple, accurate, and reliable and could provide a reference for the analysis of iodide and iodate.The simultaneous determination of iodide and iodate by reversed phase liquid chromatography with ultraviolet detection using imidazolium ionic liquids as mobile phase additives [ABSTRACT FROM AUTHOR]