[Simultaneous analysis of iodate, iodide, bromate and bromide by ion chromatography with ultraviolet detection]

An analytical method of ion chromatography with ultraviolet detection has been developed and applied for the simultaneous determination of iodate, iodide, bromate and bromide. The separation was performed on a quaternary ammonium type anion exchange column with citric acid and acetonitrile as mobile phase. The effects of the detection wavelength, the kind and concentration of the mobile phase and other parameters on separation and detection of the four ions were investigated. The retention rules were studied and the chromatographic conditions were optimized. Under the conditions of 210 nm as detection wavelength, 0.9 mL/min as flow rate, 40 degrees C as column temperature, and 1.0 mmol/L citric acid-acetonitrile (85:15, v/ v; pH 5.0) as mobile phase, the four ions were completely separated and the system peaks and other common anions didn't interfere with the determination. The detection limits of the four ions (S/N = 3) were 0.07-0.16 mg/L. The relative standard deviations of the retention times and peak areas obtained by determining samples five times continuously were below 1%. The spiked recoveries of the four anions were from 98.0% to 102%. This method has been successfully used to determine ionic liquids synthesized by chemistry laboratory and underground water samples. The results were accurate and reliable.