拟定了以碘电极指示,用硝酸银溶液作滴定剂,以Gran作图法确定终点或自动电位滴定碘离子的方法。本法适用于矿化水和海带提碘浸泡液中I-含量>10~(-5)M的测定,一般误差<1.0％,比化学法简单快速,通常在15分钟内完成。测定方法:取适量水样置于100毫升容量瓶中,如矿化度高,使稀释后的Cl-含量<1M,否则加入25毫升0.4M硫酸钾溶液作为离子强度调节液(ISA),如液样pH异常,应调节到pH约为8,稀释到刻度。全部转移到150毫升的干烧 A method of titrating iodide ions with iodine electrodes, silver nitrate solution as titrant, and Gran-plot method as endpoint or automatic potentiometric method was developed. This method is applicable to the determination of I-content> 10-5M in mineralized water and kelp for iodine soaking. The general error is less than 1.0%, which is simple and quicker than chemical method and usually finished in 15 minutes. Determination: Take the appropriate amount of water samples placed in 100 ml volumetric flask, such as high salinity, so that the diluted Cl-content <1M, or add 25 ml of 0.4M potassium sulfate solution as ionic strength adjusting solution (ISA), such as Liquid sample pH anomalies, should be adjusted to a pH of about 8, diluted to the mark. Transfer all to 150 ml dry