The adsorption capacity of UO22+ in the presence of Pb(II) and Cd(II) ions was investigated with amidoximated poly(glycidyl methacrylate) (PGMA) microbeads with an average size of 135 mu m packed in a glass column (0.5-cm i.d. and 20-cm length, flow rate = 3 mL/min) under competitive conditions. A differential pulse polarography technique was used for the determination of trace quantities of uptaken elements by the measurement of the reduction peak currents at -200 / -950, -400, and -600 mV (vs a saturated calomel 2 electrode) for UO22+, Pb(H), and Cd(II) ions, respectively. When only UO22+ was found in the eluate, its adsorption was 85.3% from a 50 mu M initial solution. However, when there was UO22+ with binary systems of Pb(II) or Cd(II), it was 78.2 and 76.3%, respectively. On the other hand, in a ternary mixure with Pb(H) and Cd(II), the adsorption was found lure of UO22+ to be 75.2% with the same initial concentration. According to the results, the competitive adsorption studies showed that these amidoximated PGMA microbeads had good adsorption selectivity for UO22+ with the coexistence of Pb(II) and Cd(II) ions. The ionic strength of the solution also influenced the UO22+ adsorption capacity of the amidoximated PGMA microbeads. (c) 2007 Wiley Periodicals, Inc.