采用火焰原子吸收光谱法间接测定饮用水中硫酸盐的含量。利用硫酸根可与钡离子定量结合产生沉淀,采用火焰原子吸收光谱法测定滤液中剩余钡离子浓度,根据钡离子消耗量间接测定硫酸盐含量。钡离子的质量浓度在200 mg·L-1以内与其吸光度呈线性关系,方法的检出限(3s)为1.6 mg·L-1。方法用于标准水样的分析,测定值的相对标准偏差(n=6)在0.72%~3.9%之间,测定结果与国家标准方法测定值相符。

FAAS was applied to the indirect determination of sulfate in drinking water. Residual barium ion in the filtrate was determined by FAAS due to the precipitation reaction stoichiometry between sulfate and barium ion. According to the consumption of barium ion, sulfate was determined indirectly. Linear relationship between values of absorbance and mass concentration of barium ion was obtained within 200 mg·L-1, with detection limit (3s) of 1.6 mg·L-1. The proposed method was applied to the analysis of standard water samples, giving values of RSD′s (n=6) in the ranges of 0.72%-3.9% and giving results in consistency with those obtained by GB method.