亚硫酸盐测定中水样的预处理

考察各物质在测定水中亚硫酸盐含量时产生的干扰。实验结果表明，亚硝酸、S^2-、COO^-均会对测定结果产生干扰，采用吹扫-酸化-水浴加热-吸收的预处理方法，可消除这些物质产生的干扰；本方法的适用范围为0~5mg/L（以SO₃^2-），最低检出限为0.1mg/L；测定结果的相对标准偏差均在2%以内，加标回收率为98.1%~103.6%。

Pretreatment of Water Sample for Sulfites Determination

The interferences of many co-existing substances in water on sulfites determination were studied. The experimental results show that nitrous acid,S^2- and COO^- may interfere with the determination result,but the interferences can be eliminated by the pre-treatment process of purging-acidification-heating in water bath-absorption；The method application scope is 0-5 mg/L (calculated as SO₃^2-),the minimum detection limit is 0.1 mg/L；The relative standard deviation is less than 2%,the addition standard recovery is 98.1%-103.6%.