碱融浸取–离子选择电极法测定固体废物中的总氟

采用氢氧化钠熔融浸取固体废物中的氟,用离子选择电极法测定其中的总氟含量。固体废物样品经氢氧化钠高温熔融后,以热纯水浸取并加入适量的盐酸使溶液呈弱碱性,去除主要干扰离子。测定氟的线性范围为5.00~500μg,线性相关系数r=0.999 6,检出限为12.5 mg/kg。6种类型固体废物样品的加标回收率在90.4%~110.0%之间,测定结果的相对标准偏差为2.3%~4.6%(n=6)。该方法样品预处理简单、重现性好、检出限低,适用于多种固体废物中总氟的测定。

Determination of Total Fluoride in Solid Waste by Ion Selective Electrode Method with Alkali Fusion Extraction

The fluorine in solid waste was obtained by leaching through the method of thermal fusion of sodium hydroxide. Total fluoride content in the leaching solution was determined by ion selective electrode method. Solid waste sample was melted by sodium hydroxide at high temperature and then the target was extracted by hot water in the condition of weak alkaline without interference. The experimental results showed that the linear range of fluoride was 5.00-500μg, the correlation coefficient of the standard curve was 0.999 6 and the detection limit was 12.5 mg/kg. The recoveries of six types of solid waste samples were between 90.4% and 110.0%,the relative standard deviation of determination results was 2.3%-4.6% (n=6). The pretreatment of the method is simple,the reproducibility is good and LOD is low,so the method is suitable for determination of total fluoride in multiple solid waste.