试样加入-离子选择性电极法测定氟

Determination of Fluorine with Ion Selective Electrode by Sample Addition

建立了一种离子选择性电极法测定氟的新方法.该方法在体积为100.0mL、量浓度为1.000×10-4mol·L-1的标准溶液中加入1.000mL较高浓度试样,加入前后测定其电动势,由这两个电动势和溶液体积计算试样的含氟量.10次测定的标准偏差S为0.0027～0.0039,相对标准偏差SR为0.017～0.039,3个水平、6次测定的回收率在95.0%～100.8%之间.该方法用于分析工业废水和化学试剂简便快速、准确可靠,得到了满意的结果.

A new method has been proposed for fluorine determination with ion selective electrode by sample addition. Using this method, 1.000 mL sample of higher concentration of fluorine ion was added to a standard solution whose concentration is 1.000×10^(-4)mol·L^(-1)and whose volume is 100.0 mL. Two cell potentials were obtained each before and after sample addition, and thus fluorine concentration was calculated by Nernst equation. The standard deviation (S) of 10 times' determination was from 0.0027 to 0.0039, the relative standard deviation (S_R) was from 0.017 to 0.039, and the recoveries of 6 times' detrmination on 3 levels were from 95.0% to 100.8%. This method is fast, simple and accurate, for satisfactory results have been obtained for the determination of wastewater and chemical reagents.