摘要
目的 通过分光光度法检测加入淀粉指示剂后的吸光度,计算盐碘滴定时消耗硫代硫酸钠的量,消除滴定终点判断所带来的误差。方法 淀粉指示剂加入前参照GB/T 13025.7—2012《制盐工业通用实验方法-碘离子的测定方法》[1],淀粉指示剂加入后采用分光光度法对吸光度进行测定,计算后可得滴定所需硫代硫酸钠的量。通过硫代硫酸钠消耗量计算碘含量。结果 该方法相对标准偏差为0.55%~3.9%、加标回收率为95%~104%、国家标准物质检测值符合证书要求。与国家标准滴定方法比较,结果在统计学上无显著性差异。结论 该方法通过分光光度法测定滴定时消耗硫代硫酸钠的量,操作简便、节省试剂和时间、灵敏度高、准确度高,减少人为观察滴定终点带来的误差,稳定性良好,满足检测需求,是一种良好的盐碘检测方法。
Objective The absorbance after adding starch indicator was detected by spectrophotometry, and the amount of sodium thiosulfate consumed during salt iodine titration was calculated to eliminate the error caused by the judgment of titration end point.Methods Before adding starch indicator, refer to GB/T 13025.7—2012 "General Test Methods in Salt Industry-Determination of Iodine".After the starch indicator was added, the absorbance was measured by spectrophotometry, and the amount of sodium thiosulfate required for titration could be obtained after calculation.The iodine content was calculated by the consumption of sodium thiosulfate.Results The relative standard deviation of the method was 0.55%-3.9%,the recovery rate of standard addition was 95%-104%,and the detection value of national standard substance met the requirements of the certificate.Compared with the traditional titration method, there was no significant difference in the results.Conclusions The method is to calculate the amount of sodium thiosulfate consumed during titration by spectrophotometry.It is simple to operate, save reagent and time, has high sensitivity and accuracy.It can reduce the error caused by human observation of titration endpoint.The method has good stability and meets the detection requirements.It is a good method for the detection of salt iodine.
作者
白皓
任宇飞
BAI Hao;REN Yufei(Laboratory of Shaanxi Institute for Endemic Disease Control and Prevention,Xi'an,Shaanxi 710003,China)
出处
《中国地方病防治》
CAS
2023年第1期33-36,共4页
Chinese Journal of Control of Endemic Diseases
关键词
碘
滴定法
分光光度法
Iodine
Titration
Spectrophotometric method
