火焰原子吸收光谱法间接测定石灰石中氯含量

提出了用硝酸溶解样品，以火焰原子吸收光谱间接测定石灰石中氯含量的分析方法。采用先往样品与校准曲线溶液中加入等量的氯离子，然后再往样品溶液中加入过量银离子使样品溶液及校准曲线溶液形成氯化银饱和溶液的方法，解决了火焰原子吸收间接法测定氯含量时微量悬浮氯化银及氯化银溶解性对测定的影响问题。在溶样过程中加入过硫酸铵氧化除去S2-、I-及大部分Br-等干扰离子，避开了过滤、蒸馏等繁琐且易受污染的操作步骤。方法相对标准偏差(RSD，n=9)为0.3 %～7.0 %。经国家标准物质验证，测定值与认定值基本符合。

Indirect determination of chlorine in limestone by flame atomic absorption spectrometry

The indirect determination method of chlorine in limestone was proposed by flame atomic absorption spectrometry after dissolving the sample with nitric acid. In this method, the same amount of chlorine was firstly added into both sample ion and calibration curve solution. Then, excessive silver ion was added to form silver chloride saturated solution, eliminating the interference of micro suspended silver chloride and its solubility during the determination of chlorine by indirect flame atomic absorption spectrometry. In the proposed method, ammonium persulfate was added in sample preparation process to oxidize and remove interference ions such as S2-, I- and most of Br-, avoiding the filtration and distillation operation procedures which were complicated and polluted easily. The relative standard deviation (RSD, n=9) of method was 0.3 %~7.0 %. This method was verified with national certified reference material, and the determination results were basically consistent with the certified values.