Spectrophotometric Determination of Cobalt (II) Using 4-(6- Nitro-2-benzothiazolylazo) resorcinol

Abstract

A sensitive and selective spectrophotometric method is proposed for the rapid
determination of cobalt (II) using 4- (6- nitro-2- benzothiazolylazo) resorcinol (6-
NO2BTAR).The reaction between 6-NO2BTAR and Cobalt (II) is instantaneous at pH
6.0 and the absorbance remains stable for over 24h. The method allows the
determination of cobalt over the range (1-8) μg/ml with molar absorptivity of (4857.1)
L.mol-1.cm-1 and features a detection limit of (0.2) μg/ml at 458 nm. The precision
(R.S.D%<1%) and the accuracy obtained were satisfactory. The proposed method has
been successfully applied to the determination of cobalt in filling.