Spectrophotometric determination of cobalt by the 2,2'-dipyridil ketoxime method (II) - Choice of solvent and studies about colored compound extration

Abstract

This paper belongs to a series of articles about the 2,2'-dipyridyl ketoxime method for the espectrophotometric determination of cobalt. It presents a study on the extration procedure of the color compound formed by using chloroform or dichloromethane. It was established that the former is more efficient than the latter one. The region of maximum absorption of the color compound in chloroform is between 375 and 390 nm. On the other hand, 3.0 ml of the solvent, is sufficient for the extration of the water-soluble chelate obtained from 5.0 micrograms of cobalt, with a shaking time of 15 seconds. The color compound is stabile both in contact with the solutions (120 minutes) and after extration with chloroform (180 minutes).