ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 9, Number 2
JKCSEZ 9(2)
April 20, 1965 

Spectrophotometric method for the determination of Co(Ⅱ) is developed based on the fact that Co(Ⅱ) forms a stable red complex with 7-nitroso-8-hydroxyquinoline-5-sulfonate at pH 4. 5. The absorbance is measured at 528 mμ, 25℃. Beer's law is followed in the concentration range of 0. 3 to 6. 0 p.p.m. of Co(Ⅱ) and molar extinction coefficient of the complex was 1. 1 × 104. Of the diverse ions checked, Fe(Ⅱ), Fe(Ⅲ), Cu(Ⅱ), Mn(Ⅱ), Hg(Ⅰ), CN-, EDTA interfere. The composition of the complex is found to be 3:1 ligand to metal species by mole ratio and continuous variation methods.