Spectrophotometric determination of cobalt (II)‎ using 4-(6-bromo 2-benzothiazolylazo)‎ orcinol as an organic reagent

Abstract EN

Simple and selective spectrophotometric method was proposed for the rapid determination of cobalt(II) using 4-(6-Bromo 2-benzothiazolylazo) Orcinol(6-BrBTAO).

Alcoholic solution of 6-BrBTAO form a 1:2 pink complex with cobalt(II) ions at pH ranges 5.0-10.0, absorbing maximum at 514 nm.

The molar absorptivity and the Sandell’s sensitivity of the complex are 2.574 x 103L mol-1 cm-1 and 0.022μg.cm-2 respectively.

Under the optimum established conditions, which led to a detection limit of 0.51 μg.mL-1 of Co (II) and concentration range of 0.7-30 μg.mL-1 with percent recovery of 100.43 ± 1.23.

The precision for seven replicate measurements of 15 μg.mL-1 Co(II) was of 1.7 %.

The method was applied to the determination of cobalt in some vegetables samples such as radish, carrot and spinach with satisfactory results.