Substoichiometric masking-II Determination of traces of cobalt in nickel salts and metallic nickel.
Cobalt is determined in the presence of large amounts of nickel by masking the latter substoichiometrically by addition of xxx 98% of the theoretically required amount of EDTA. The "free nickel" :cobalt ratio is thereby decreased below the critical value and the cobalt is extracted as the green cobalt(III)-PAN complex into chloroform. Small amounts of nickel-PAN formed are destroyed by a subsequent EDTA-hydrochloric acid treatment. The absorbance of the treated extract is measured at 635 mmu. Copper, zinc, cadmium and iron do not interfere in ratios (to cobalt) of 500:1, 100:1, 100:1 and 10:1, respectively.
Flaschka
H
H
School of Chemistry, Georgia Institute of Technology, Atlanta, Ga. 30332, U.S.A.
Garrett
J
J