Application of derivative spectrophotometry to simultaneous determination of nickel and mercury with diethylenetriaminepentaacetic acid (DTPA)

The application of derivative spectrophotometry to the simultaneous determination of nickel(II) and mercury(II) with diethylenetriaminepentaacetic acid (DTPA) is described. The procedure doesn't require equations to be solved, and it is suitable for concentrations of 0.40-1.80 mg ml(-1) of nickel and 0.20-0.70 mg ml(-1) of mercury. The main interferences, both anionic and cationic, are easily eliminated. The method was applied to different aqueous matrices and it was compared with an atomic absorption (AA) method. Good results were obtained.