铬鞣革剂中硫酸根的定量分析

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%

QUANATITATIVE ANALYSIS OF SULFATE ION IN CHROME TANNING AGENTS

Barium sulfate has been used in gravimetric determination of sulfate ion inchrome tanning agents. In purifying the Barium Sulfate precipitate, the followingis important from the analytical point of view: 1. An excess of 5% EDTA is to be added to the solution and the solution isboiled 25--30 min in the HAC--NaAC buffer solution at the pH 4. 5--5. 0 maskingchromium. 2. To prevent the coprecipitation of Ba (R--SO_3)_2 With the BaSO_4, alcoholsolution is to be added to the solution. 3. It is feasible to purify the BaSO_4 precipitate by repreeipitation the aminatedsolution with EDTA added to it makes BaSO_4 form soluble Bay~(2-) Complex and thenat the pH 4. 5--5. 0 Bay~(2-) reprecipitate into BaSO_4. This method is applicable to theComplicated system of guantitative determination of sulfate ion.