Substoichiometric Isotope Dilution Analysis of Indium by Liquid Scintillation Counting

A sensitive and selective substoichiometric isotope dilution method for the determination of trace amounts of indium is described. The method is based on the extraction of its ionassociation complex with substoichiometric amount of Aliquat-336 into toluene from 0.7 M KBr and 4.0 M H2SO4. The beta activity of indium-114 is measured by liquid scintillation counting. The counting efficiency was found to be 92%. The ease with which indium can be quantitatively collected over ferric hydroxide is put to advantage in developing the above method. The collection method in conjunction with the substoichiometric method is used to determine indium in the flue dust and zinc ore. The detection limit was found to be 0.5 μg in 100 ml of aqueous volume. © 1993, Walter de Gruyter. All rights reserved.