Under the existence of protective agents and in acidic solution, fine and uniform suspended particles barium sulfate BaSO4 formed by sulfate radical SO42- and barium ions Ba2- make the solution turbid, and there is a proportional relationship between the turbidity and the content of sulfate radical SO42- in sample solution. On the basis of the principle stated above, a spectroturbidimetry for the determination of content of sulfate radical SO42- in cobalt chloride with glycerol as stabilizer is established. Influences of factors such as sonic oscillation, concentration of glycerol, and stable time on the test results are studied, and the various conditions are optimized. Cobalt affects the determination, but this effect can be eliminated by adding the cobalt chloride solution containing no sulfate radical into the standard contrasting solution to make the concentration of cobalt in standard contrasting solution in consistency with that in sample solution. The detection range of sulfate radical in cobalt chloride solution is 0% to 0. 1% , the relative standard deviation is 0. 84% to 3. 4% , and the recovery rate is 98% to 101%. The method has been used for the determination of sulfate radical in cobalt chloride products for almost two years with better results. The method is suitable for promotion.%基于在酸性溶液中、有保护剂存在的条件下,SO42-与Ba2+形成细微均匀的BaSO4悬浮微粒使溶液浑浊,其浊度与试样中硫酸根(SO42-)含量呈正比关系的原理,建立了以丙三醇为稳定剂测定氯化钴中硫酸根(SO42-)含量的分光光度比浊法.考察了超声振荡、丙三醇浓度、稳定时间等因素对检测结果的影响,并对各条件进行了优化.钴背景对测定有影响,但这种影响可以通过在标准比对液中加入不含硫酸根的氯化钴溶液,使标准比对液中钴浓度与样品中钴浓度一致而消除.该方法对氯化钴中硫酸根的检测范围为0％～0.1％,相对标准偏差为0.84％～3.4％,回收率为98％～101％.方法用于氯化钴产品中硫酸根的检测已近两年,效果较好,适于推广.
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