Trace Analysis of Co(II) in Underground Water by Spectrophotometric and AAS Methods after Preconcentration
Department of Analytical Chemistry, Faculty of Chemical and Food Technology, Slovak Technical University, Bratislava, Slovakia
Extraction results, spectral properties and composition of of the Cupral complex of Co(III) are presented in the paper. The dependences of extraction recovery on pH of the water phase and on the reaction time of the complexation were studied. It was found that the absorption band at λ = 325 nm (ε 33 300) is the most suitable for the determination of Co(II). The detection limit 4.1·10-2 μg mL-1 could be achieved. The optimal reaction time of the chelate formation was 5 min and the pH range for extraction of the Co complex was 8.5-9.2. A spectrophotometric method of the slope of calibration dependences were used to confirm the metal/ligand ratio (1 : 3). The spectrophotometric method was used, after ion-exchange separation, for the determination of Co(II) in underground water from the neigbourhood of a chemical factory. The results were compared with those obtained by AAS under optimal conditions.
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