Selective Separation of Cerium from Lanthanides by Extractive Photometry Using HDBE as Novel Reagent

Striking similarities in properties of lanthanides make their separation a difficult task. Development of highly selective analytical reagent hexane-2,5-dione-bis(ethylenediamine) HDBE that forms brown coloured complex with Ce(IV) which is quantitatively extracted into xylene at pH 6.4. Transfer of extracted complex to organic phase is very fast (<1min.). Optimum concentration of reagent required for complexation and full colour development is very low (0.8 cm3 of 0.1 % HDBE). Absorption maximum exhibited at 518 nm. Beer’s law is obeyed in the detectable range 0.3-4.0 ppm. The molar absorptivity and Sandell’s sensitivity values are 0.421·10⁴ dm³· mol^-1·cm^-1 and 0.017 µg·cm^-2 respectively. The present method is time honoured, permits selective separation of cerium from associated lanthanones using HDBE as a novel complexing agent.