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本文要解决的问题是,在ICP-AES方法中利用化学氧化反应来提高对碘的检测能力,并将此法应用于测定海水中的碘含量。有氧化反应的情况下,送样系统的记忆效应较大,这是与系统表壁对挥发性碘分子的吸附作用有关的。减小雾室体积,缩短塑料连接管,可以降低记忆效应。采用氧化反应可以使传输效率由1％增至～80％;碘的检测限由37ng/ml降为2ng/ml。用硝酸作氧化剂测定海水中的碘,存在着明显的干扰效应。干扰的实质是一定浓度的盐酸(>0.5N)与氧化所得的碘分子之间的作用。为了避免盐酸的干扰效应,采用在低酸度下起作用的氧化剂,如NaNO_2和H_2O_2,可以获得比较满意的结果。海水中碘的定量测定下限为30ng/ml;方法的标准偏差为3—8％。
The problem to be solved in this paper is the use of chemical oxidation in the ICP-AES method to improve the detection of iodine and to apply this method to the determination of iodine in seawater. In the case of an oxidation reaction, the memory effect of the sample delivery system is larger, which is related to the adsorption of volatile iodine molecules on the surface of the system. Reduce the volume of the mist chamber, shorten the plastic connecting pipe, can reduce the memory effect. The oxidation efficiency can increase the transfer efficiency from 1% to 80%, and the detection limit of iodine from 37 ng / ml to 2 ng / ml. Determination of iodine in seawater using nitric acid as oxidant has obvious interference effect. The essence of the interference is the action between a certain concentration of hydrochloric acid (> 0.5 N) and the iodine molecule resulting from the oxidation. In order to avoid the interference effect of hydrochloric acid, the use of oxidants such as NaNO 2 and H 2 O 2 which work at low acidity can obtain more satisfactory results. The lower limit of quantitation of iodine in seawater is 30 ng / ml; the standard deviation of the method is 3-8%.