Speciation analysis on europium(III) using laser-induced breakdown spectroscopy

The generation of Eu(III) precipitation and the Eu sorption on TiO2 particles in aqueous solution were studied using laser-induced breakdown spectroscopy (LIBS). The plasma emission intensity vs. the Eu concentration plot showed a good linearity in the concentration range of 6.6 x 10(-3) M - 1.3 x 10(-2) M for Eu aqueous solution at pH 1.1 and 6.6 x 10(-5) M - 6.6 x 10(-4) M for Eu2O3 suspension at pH 5.0. It was found that the generation of Eu precipitation was detected through a drastic increase of plasma emission intensity of Eu. The results suggested that LIES is useful for analyzing the particles and the precipitation of Eu in aqueous solution, even if the Eu ion concentration is higher by orders of magnitude. Furthermore, we could measure the plasma emission of Eu ions sorbed on TiO2 particles under the conditions where the plasma emission of Eu ions could not be detected in the absence of TiO2. Hence, LIES technique is considered to be useful to study the colloid generation of Eu.