硫氰酸铁-亚硝酸盐催化分光光度法测定水中碘

Method for iodine determination in water with ferric thiocyanate-nitrite Catalytic Spectrophotometry

目的探讨取代剧毒试剂三氧化二砷（AS2O3）的水中碘的催化分光光度法。方法在稀硝酸介质中,研究碘催化硫氰酸铁褪色反应的适宜条件,建立测定水中微量碘含量的催化动力学光度法。结果方法的线性范围为6~100μg/L,相关系数r=-0.9997,检出限为1.77μg/L碘（取样量1mL,1.77ng碘）,回收率在97.20%~99.95%。结论本方法较砷铈催化分光光度法检测水中碘的精密度和准确度结果满意,可完全不使用剧毒物质三氧化二砷,减小了对检测人员健康的损害和环境污染的风险。

Objective To study a new catalytic spectrophotometry methodfor iodine determination in water,i. e with ferric thiocyanate-nitrite instead ofextremely toxic substance（ AS2O3）. Methods In dilute nitric acid,the suitable for the conditions of iodine catalytic reaction of ferric thiocyanate was worked out,and the catalytic spectrophotometric determination of iodine in water was developed,the standard curve,linear range,detection limit,determination precision and accuracy was calculated. Results The linear range was 6 ~ 100μg /L,the linear correlation coefficient r =-0. 9997,the detection limit was 1. 77 μg /L iodine（ sample 1mL,1. 77 ng iodine）,the recovery was 97. 20% ~ 99. 95%. Conclusion The precision and accuracy of this method is equal to the As（ III）-Ce4 ＋catalytic spectrophotometry,but without the use of highly toxic arsenic trioxide as well as reducing the risk of detection personnel health and environmental pollution.