碘元素检测仪自动测定盐碘含量的方法研究

A method of automatic determination of salt iodine by iodine element detector

目的建立应用碘元素检测仪, 通过砷铈催化分光光度法自动测定盐碘含量的方法(以下简称本方法), 为深入研究盐碘检测技术提供参考。方法采用本方法测定盐碘含量, 评价方法的线性范围和检出限、精密度、准确度(盐碘标准物质GBW10006y、GBW10007y测定及加标回收实验);应用本方法与国家标准推荐的氧化还原滴定法同时测定35份盐样碘含量, 并进行结果比对。结果本方法在碘浓度为50 ~ 600 μg/L标准曲线范围内有良好的线性关系, 相关系数的绝对值均> 0.999 0, 检出限为5.0 mg/kg。测定低、中、高3种碘浓度盐样, 碘浓度的相对标准偏差均< 6.0%。盐碘标准物质GBW10006y、GBW10007y的测定结果均在给定值范围内;在盐样中分别加入3个碘浓度(6.0、10.0、30.0 mg/kg), 平均回收率范围为96.7% ~ 105.0%, 总平均回收率为100.9%。方法比对结果显示, 本方法与氧化还原滴定法的盐碘测定结果差异无统计学意义(t = - 1.54, P = 0.132)。结论本方法测定盐碘含量具有准确度高、精密度好及线性范围宽等优点, 适用于盐碘监测中大批量样品的检测。

Objective To establish a method for automatic determination of iodine level in salt by arseniccerium catalytic spectrophotometry using an iodine element detector(hereinafter referred to as this method),and to provide reference for in-depth study of salt iodine detection technology.Methods This method was used to determine the iodine level in salt,and the linear range,detection limit,precision,and accuracy(determination of salt iodine standard substance GBW10006y and GBW10007y,and addition recovery experiment)of this method were determined.The iodine level of 35 salt samples was determined by this method and redox titration method recommended by the national standard,and the results were compared.Results This method had a good linear relationship within the range of 50-600μg/L standard curve,the absolute value of the correlation coefficients was>0.9990,and the detection limit was 5.0 mg/kg.The relative standard deviation of iodine concentration in salt samples with low,medium and high iodine concentrations were all<6.0%.The determination results of salt iodine standard substance GBW10006y and CBW10007y were within the given value ranges;three iodine concentrations(6.0,10.0 and 30.0 mg/kg)were added to the salt samples,with an average recovery rate of 96.7%to 105.0%,and a total average recovery rate of 100.9%.The method comparison experiment showed that there was no statistically significant difference between the salt iodine determination results of this method and the redox titration method(t=-1.54,P=0.132).Conclusion This method has the advantages of high accuracy,good precision and wide linear range in determining salt iodine,and is suitable for the detection of large quantities of samples in salt iodine monitoring.