摘要
建立了一种选择性电极法测定粗氢氧化钴中微量氟的方法.样品经硝酸溶解后,用氟离子选择电极在离子电位计上测定溶液的电位差计算样品中氟含量.本文实验了样品的溶样方法、总离子强度调节缓冲溶液的最佳加入量,进行了共存离子干扰实验,证明样品中钴、锰、镁、铜、铝、铁、钙对氟元素的测定无明显干扰.对刚果(金)某中资企业实际生产的粗氢氧化钴样品进行测定,氟元素的相对标准偏差(RSD,n=11)在1.59％～4.59％之间,加标回收率为98.29％～102.19％,氟离子的线性范围为0.05～20.0 μg/mL,本法可准确测定粗氢氧化钴中0.0025％～0.5％的氟含量,测定结果和外检结果相比较,结果吻合,令人满意.
Abstract
It established a method that selective electrode potentiometry for the determination of trace fluoride.Nitric acid is used for the dissolution of the sample,and the fluoride content in the sample was calculated by solution potential difference,which is measured by the ion potentiometer of the fluorine ion selective electrode.The paper described the sample dissolution method,the best addition amount of buffer solution for adjustment of total ionic strength,the co-existing ion interference experiments were carried out,experiments results show,there's no obvious interference in fluoride elements determination caused by cobalt,manganese,magnesium,copper,aluminum,iron,and calcium in samples.The determination of the crude cobalt hydroxide sample produced by one Chinese-funded enterprise in Democratic Republic of the Congo was carried out,the relative standard deviation of fluorine(RSD,n=11)is in the range of 1.59％～4.59％,the recovery rate is 98.29％～102.19％,the linear range is in the range of 0.05～20.0 μg/mL,the fluorine content in the range of 0.0025％～0.5％can be measured accurately by using the method,the test results are combined with the external inspection results,the results are encouraging.
维普
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