CAPILLARY ZONE ELECTROPHORESIS OF LANTHANOID ELEMENTS AFTER COMPLEXATION WITH AMINOPOLYCARBOXYLIC ACIDS

Capillary zone electrophoresis was applied to the separation of the la nthanoid elements chelated with aminopolycarboxylic acids. Several ami nopolycarboxylic reagents (ethylenediaminetetraacetic acid and chemica lly similar analogues) were varied in an effort to optimize the separa tion resolution. By varying the pH and concentration of the electropho retic buffer, it was also possible to manipulate the migration times, efficiency and detectability. Optimum resolution and analysis time (wi thin 12 min) for lanthanoids(III), and also scandium(III) and yttrium( III), was achieved with cyclohexane-1,2-diaminetetraacetic acid (CDTA) and simple electrolytes such as a berate buffer (20 mmol l(-1), pH 11 .0) containing 1 mmol l(-1) CDTA. Determination of the lanthanoid comp lexes was performed by direct UV detection at 214 nm. The calibration graphs were linear (r > 0.99) over at least two orders of magnitude of concentration. The detection limits were at the mid-ppb level and the relative standard deviation was about 2.8% at the mid-calibration ran ge. The method appeared to be feasible to determining the lanthanoid e lements in nuclear fuel waste, and may be also recommended for assessi ng lanthanoid impurities in nuclear fuel.