Ion-Exchange Films for Luminescence Spectrometry of Rare-Earth Ions

Thin, initially transparent films made of variants of a polymeric cation-exchange material have been found to be useful for facilitating the luminescence detection and quantitation of several rare-earth ions dissolved in aqueous solutions. A film of this type is prepared in an acid form, then converted to a Ca2+salt form. The acid form of the material consists of polyacrylic acid entangled in a matrix of insolubilized or further cross-linked polyvinyl alcohol. The conversion to the salt form is effected by exposing the film to Ca(OH)2.