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引言海水含碘极微,平均含量约为50～60微克/升。海水中的碘主要以碘酸根(IO_3~-)和碘离子(I~-)形态存在,此外还含有微量的有机态碘。在六十年代初还缺乏准确测定海水含碘量的方法,近代分析技术已发展了砷铈催化法、中子活化法、电流滴定法、微分脉冲极谱法、碘酸盐光度法和淀粉比色法等,但以砷铈催化法的研究为多。砷铈催化法是利用碘离子对高铈一亚砷酸氧化还原反应具有催化作用的原理来测定微量碘。建立这一方法的是Sandell和Kolthoff,但最先将这个方法用于测定海水含碘量的是Dubravicic,后经Barkley等人加以改进。Truesdale又进一步研究砷铈催化法的动力学、最佳条件,并设计了自动分析的方法。经过改进,砷铈催化法逐渐成了一种简单、灵敏的测定海水含碘量的方法。但这一方法必须严格控制反应条件才有良好的灵敏度与重现性,因此有必要对其主要影响因素的作用作进一步研究。
INTRODUCTION Seawater contains very little iodine, with an average content of about 50-60 μg / L. The iodine in seawater is mainly in the form of iodate (IO_3 ~ -) and iodide (I ~ -), in addition to trace amounts of organic iodine. In the early 1960s, there was still a lack of accurate methods for the determination of iodine in seawater. Modern analytical techniques have been developed for the arsenic-cerium catalytic method, the neutron activation method, the current titration method, the differential pulse polarography, the iodate photometric method and the starch ratio Color method, but arsenic cerium catalyst method for more. Arsenic cerium catalytic method is the use of iodine ions on the reaction of cerium a-arsenic redox reaction has the catalytic principle to determine trace iodine. This method was established by Sandell and Kolthoff but the first method used to determine iodine in seawater was Dubravicic, which was later modified by Barkley et al. Truesdale further studied the arsenic cerium catalyst kinetics, the best conditions, and designed the method of automatic analysis. After the improvement, arsenic cerium catalytic method has gradually become a simple and sensitive method for the determination of iodine in seawater. However, this method must be controlled strictly reaction conditions have good sensitivity and reproducibility, it is necessary to further study the role of its main influencing factors.