Spectrophotometric determination of Cobalt II with PAN using Flow injection technique.

Sherwan O. Baban

College of Education Science, Salahaddin University

A simple, rapid, reproducible and sensitive spectrophotometric method for
determination of Cobalt (Co
2+) was investigated .The method was based on the
interaction of Co
2+ with 1-(2-pyridylazo)2-naphthol (PAN), in the presence of
buffer pH 6 (CH
3COOH + CH3COONH4) to give a highly colored species of a
molar ratio 1:2 (Co:PAN) .Beers law was obeyed in the range of (0.1-2.5)
μg/ml with the molar absorptivity of 3.77x10
4 L.mol-.cm- at λ max 525 nm.
The method was adapted to semi automated flow injection system .The molar
absorptivity was 0.16x10
4 L.mol-.cm- at λ max 525 nm .Beers law was obeyed
in the range (0.3-10) μg/ml. The precision and accuracy studied to both
systems. The method was applied successfully to the assay of Co
2+ in real
sample such as real water and waste water, and was well agreed with its
certified value.

Key Words: Cobalt, PAN, Spectrophotometry, flow injection. 


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