Rapid Strategy for Sequestration of Am(III) by a Phosphotungstate Composite: Structural Insights and Bioanalytical Applications.

Rapid and reliable determination of americium in human urine is crucial during radiological emergencies; however, conventional radiochemical methods are labor-intensive and require several days for analysis. In this work, we present a simple, rapid, and efficient method for the sequestration and quantification of Am(III) using a composite resin prepared by exchanging the chloride ions of DOWEX 1 × 8 resin with lacunary phosphotungstate anions (PW117-). FTIR, NMR, UV-Vis, SEM, TGA, photoluminescence, and XPS analyses confirmed PW11 incorporation into the resin and its strong interaction with the metal ion. The composite resin demonstrated a very high affinity for Am(III) and Eu(III) (Kd > 105 mL/g) with rapid equilibrium extraction (30 min), while exhibiting significantly lower affinity and slower kinetics for U(VI) at pH 6.0, enabling effective selectivity. Both slope and photoluminescence studies indicated that the most probable species extracted by the composite resin was the 1:1 (Am: PW11) species. The application of the composite resin to human urine samples resulted in a 70.6 ± 3.1% recovery (n = 7) of americium when spiked at a very low concentration (1.20 ± 0.02 Bq/100 mL). The present method offers a simple, reliable, and promising alternative for high-throughput radiobioassays during emergency response scenarios, reducing the processing time from 4-5 days to ∼7 h.