Atomic absorption determination of indium after extraction with di-(2-ethylhexyl)phosphoric acid

The equilibrium data show that indium can be quickly extracted from acidic aqueous solutions by di-(2-ethylhexyl)phosphoric acid in methyl isobutyl ketone. In this polar solvent the species ML3·HL is extracted. The overall extraction constant is higher than that for other tervalent metals. The extraction process can be combined with AAS determination of the indium. The method is fast because stripping is not necessary, and the organic phase can be analysed directly by AAS. Use of a 5:1 v/v aqueous: organic phase ratio increases the sensitivity. In the pH-range used the method has good selectivity. © 1987 Springer-Verlag.