Spectrophotometric Determination of Cobalt with Thioglycolic Acid

Abstract

The yellow-red color of cobalt(II) with thioglycolic acid (sodium salt) having maximum absorbance at 358 mμ has been employed as the basis for a spectrophotometric method for the quantitative determination of cobalt. The system was found to obey Beer's law between the concentration limits of 1.0 to 10.0 × 10−6 gram of cobalt(II) and to remain stable for over 48 hours at room temperature. The effects of pH, reagent concentration, time of heating, and aging were studied. Interference by heavy metals such as copper, nickel, iron, chromium, molybdenum, uranium, vanadium, etc. was prevented by extracting cobalt from the solutions. © 1961, American Chemical Society. All rights reserved.