Simultaneous kinetic-spectrophotometric determination of Nb(V) and Ta(V) using H-point standard addition

A simple, rapid, precise and accurate kinetic method for simultaneous spectrophotometric determination of Nb(V) and Ta(V) is described. This method is based on the difference between the rate of the reaction of Nb(V) and Ta(V) with 4-(2-pyridylazo)resorcinol (PAR) in the presence of tartaric acid. H-point standard addition method (HPSAM) was used to resolve the mixtures. The results showed that Nb(V) and Ta(V) can be determined simultaneously in the ranges of 0.10-5.0 and 0.50-12.0 mu g mL(-1), respectively. The proposed method was successfully applied to the simultaneous determination of Nb(V) and Ta(V) in several alloy samples.