[Simultaneous spectrophotometric determination of trace ferrum and cobalt with 5-Br-PADAP and Tween-80].

A new simultaneous method for the determination of ferrum and cobalt with 5-Br-PADAP by spectrophotometry in the presence of Twen-80 is studied. The results showed that in pH = 3.4 HAc-NaAc buffer medium, ferrum and cobalt can formed colored complexes with 5-Br-PADAP. Its maximum absorption wavelengths are at 585 nm. Beer's law is obeyed for the concentration of ferrum in the range of 0-10 micrograms.25 mL-1 and 0-12 micrograms.25 mL-1 of cobalt. The apparent molar absorptivities are epsilon 585Fe = 7.18 x 10(4) and epsilon 585Co = 9.27 x 10(4) respectively. This method has been applied to the determination of ferrum and cobalt in water sample with satisfactory results.