Determination of europium with solid-surface room-temperature phosphorescence optosensing

Abstract

Immobilization of the complex formed by thenoyltrifluoroacetone (TAA) with Eu^III on the chelating resin Chelex 100 packed in a flow cell can induce the phosphor to have room-temperature phosphorescence behaviour in aqueous solution. Based on this phenomenon, a new room-temperature phosphorescence optosensing method in an aqueous flow system has been established to determine europium ions at 2.0 × 10^–9–1.0 × 10^–7 mol dm^–3. Using a response time of 60 s, the detection limit was 1.0 × 10^–9 mol dm^–3 Eu³⁺. Using 0.5 mol dm^–3 HCl solution, the sensing layer, coordinated by the Eu-TTA complex, can be regenerated quickly and completely. The response mechanism of the optosensing was also studied in detail. The present method has been applied to the determination of europium ions in three synthetic samples.