毛细滴管数滴微型滴定法现场快速测定食盐中的碘酸钾

Drops Counting of Capillary Burette Micro Titration for Fast Determination of Potassium Iodate in Edible Salt

毛细滴管数滴微型滴定法以价格不足0.3元/支的聚乙烯塑料滴管为量器进行滴定分析,不仅仪器结构简单、小巧、价廉、携带方便,而且试剂用量少,测定简便、快速、准确。用该法测定食盐中的碘酸钾,当毛细滴管规格为0.01～0.02ml/滴,滴定剂用量控制在60～90滴时,相对扩展不确定度Urel(C)约为1.3%,加标回收率=98.4%～101.5%,RSD=0.77%～1.6%,符合GB5009.42-2003的规定。采用数滴法进行现场快速测定,有利于碘盐生产及流通渠道中日常的质量和卫生监督工作的正常开展,值得推广应用。

Drops counting of capillary burette micro titration with polyethylene burette to carry on titration analysis, the apparatus is simple, small, cheap, easy to carry, and less reagent consumed, while the determination is fast and correct. To determine potassium iodate in edible salt, the specification of home-made capillary burette is 0.01-0.02 ml/drop, and the dosage of standardization solution is controlled in 60-90 drop, with relative expand uncertainty about 1.3%, reclaim rates 98.4%- 101.5%, and RSD 0.77%- 1.6%, in accordance with stipulation of GB5009.42-2003. The methods used to assay edible salt production and daily sanitation surveillance work, can report rapidly the analysis results, worthy popularization.