Cupferron separation for the determination of tantalum in high-purity iron and low alloy steel by ICP-AES

For the determination of Ta (> 0.0005 mass %) in iron and low-alloy steel spectrophotometric methods, e.g., after the extraction of the Ta-Victoria Blue B complex by benzene, are generally used. To avoid the application of poisonous benzene as extracting solvent and to improve the detection power, an ICP-AES method after the separation of Ta by coprecipitation with cupferron has been developed. The detection limit (3σ) of 0.6 μgTa/g is lower in comparison with spectrophotometric methods. Therefore, the method also allows the determination of Ta-concentrations in the μg/g-range in high-purity iron.