Solid Phase Extraction Method for the Determination of Cobalt in Water Samples on Duolite XAD-761 Resin Using 4-(2-Pyridylazo) Resorcinol by FAAS

A new solid-phase extraction method was developed for trace analysis of cobalt on Duolite XAD-761 resin by using flame atomic absorption spectrometry (FAAS). The optimum experimental conditions for the quantitative sorption of Co(II)-PAR (cobalt chelates with 4-(2-Pyridylazo) resorcinol), pH, effect of sample flow rate, concentration of eluent, sorption capacity of resin and the effect of diverse ions on the preconcentration of analytes have been investigated. The optimum pH values for quantitative sorption of Co (II)-PAR were between 5 and 7.5. Eluted process was performed by 4 mL ethanol. The sorption capacity of resin was determined to be 8.6 mg g–1 for cobalt with a preconcentration factor of 150. In optimized conditions, the detection limit for cobalt ions was found to be 0.36 μg L– 1. The accuracy of the proposed procedure was checked by using NIST 1573 a tomato leave as a standard reference material. The achieved results were in good agreement with certified values. The proposed method was applied for the determination of cobalt in different water samples, such as city line, geothermal, river and lake.