Abstract： 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.
