Ion beam induced luminescence analysis of europium complexes in styrene-divinylbenzene copolymer-coated spherical silica by proton and argon ion beams irradiation

Abstract

Ion beam induced luminescence (IBIL) analysis of adsorbents containing Eu complexes was carried out using a 3-MV single-ended accelerator and an azimuthally varying field cyclotron to evaluate structures of complexes in an extraction chromatography. Some adsorbents were prepared by impregnating a styrene-divinylbenzene copolymer-coated porous silica particle (SiO2-P) with extractants. The IBIL spectra of Eu complexes in the adsorbents produced some differences depending on the kinds of extractants. The experimental results imply that the difference in the IBIL spectra of Eu complexes in the adsorbents is caused by the difference in the structures. The only clear luminescence peak in the alkyl diamide amine (ADAAM) with n-octyl and 2-ethylhexyl alkyl chains (ADAAM(Oct, N(EH))) adsorbent was not observed by H+ ion beam irradiation. Meanwhile, the luminescence of Eu could be detected by irradiation of an Ar8+ ion beam. The luminescence of Eu complexes is presumed to be easily detected by high linear energy transfer (LET) beam irradiation. The symmetric properties of Eu complexes were evaluated with the luminescence due to the 5D0 → 7F2 transition, and it is implied that ADAAM with 2-ethylhexyl alkyl chains (ADAAM(EH, N(EH))) is a high asymmetry property. The luminescence intensity of Eu complexes in the adsorbent decreased with the ion beam irradiation because extractants were damaged by the ion beam. This phenomenon was clearly observed by irradiation of high LET ion beam, Ar8+.