Determination of Trace Amounts of Cobalt at sub-μg 1−1Level by Solid Phase Spectrophotometry

Abstract
A very sensitive method for the determination of trace amounts of cobalt has been developed, based on Solid-Phase Spectrophotometry (SPS). The method is based on the fixation of cobalt (II) as the 4- (2-pyridilazo) resorcinol complex on an anion-exchange resin. Resin phase absorbance is measured directly, and it allows the determination of cobalt (with a RSD of 2.4 %) in the range of 0.4–3.8 μg 1−1. The method was applied to the determination of cobalt (II) in different samples, namely beers, drugs and waters.