本文着重研究用硫酸钡重量法测定SO_4~(2-)的含量时,采用EDTA和HAC联用络合剂掩蔽干扰离子Cr~(3+),在乙醇介质中消除有机磺酸基R—SO_3的干扰。并在氨性溶液中使初沉淀的BaSO_4溶解,再在酸性溶液中二次沉淀BaSO_4,从而得到精制的BaSO_4。实验结果表明,该法适用于复杂体系中SO_4~(2-)的定量分析,测定误差小于0.30% This article focuses on the determination of SO_4 ~ (2-) content with barium sulfate gravimetric method, the use of EDTA and HAC complexing agent to mask the interference ions Cr ~ (3 +), the elimination of organic sulfonic acid group R-SO_3 Interference. And the primary precipitated BaSO_4 was dissolved in the ammonia solution, followed by secondary precipitation of BaSO_4 in acidic solution to obtain purified BaSO_4. The experimental results show that the method is suitable for the quantitative analysis of SO_4 ~ (2-) in complex system with the error less than 0.30%