Xie Zhihai, Zhao Jingchan
Department of Chemistry, Northwest University, Xi'an 710069, PR China.
Talanta. 2004 May 28;63(2):339-43. doi: 10.1016/j.talanta.2003.10.050.
A very simple and sensitive reverse flow injection method is described for the determination of iodate and iodide. The iodate reacts with excess iodide in acidic medium to form tri-iodide, which can be spectrophotometrically monitored at 351nm, and the absorbance is directly related to the concentration of iodate in the sample. The determination of iodide is based on oxidizing iodide to iodate. The calibration curve is linear in the range of 0.02-3.0mugml(-1) I with r(2)=0.9998, and the limit of detection is 0.008mugml(-1) I. The chemical and flow injection variables were studied and optimized to make the procedure suitable for quantitating iodate and iodide in table salts. It is shown that the reverse flow injection analysis could greatly improve the sensitivity and precision for determination of iodate with a relative standard deviation of 0.9%. A complete analysis, including sampling and washing, could be performed in 35s. The procedure was applied successfully to the determination of iodate and iodide in table salts, and the results were statistically compared with results determined by standard iodometry method.
本文描述了一种用于测定碘酸盐和碘化物的非常简单且灵敏的反向流动注射法。碘酸盐在酸性介质中与过量碘化物反应形成三碘化物，可在351nm处进行分光光度监测，吸光度与样品中碘酸盐的浓度直接相关。碘化物的测定基于将碘化物氧化为碘酸盐。校准曲线在0.02 - 3.0μg/ml I范围内呈线性，r² = 0.9998，检测限为0.008μg/ml I。对化学和流动注射变量进行了研究和优化，以使该方法适用于定量食盐中的碘酸盐和碘化物。结果表明，反向流动注射分析可大大提高碘酸盐测定的灵敏度和精密度，相对标准偏差为0.9%。一次完整的分析，包括进样和清洗，可在35秒内完成。该方法成功应用于食盐中碘酸盐和碘化物的测定，并将结果与标准碘量法测定的结果进行了统计学比较。
