title: Preconcentration of lanthanides from natural waters with a lipophilic crown ether carboxylic acid.
abstract: Lipophilic crown ether carboxylic acids such as 2-(sym-dibenzo-16-crown-5-oxy)stearic acid with a cavity size comparable to the ionic radius of rare-earth elements are selective chelation agents for preconcentration and separation of lanthanides from natural waters for NAA. Interfering matrix elements such as sodium and bromine can be simultaneously eliminated during the extraction. The lanthanides can be back-extracted into a dilute acid solution for NAA, thus providing a large preconcentration factor. This two-step extraction method appears suitable for the determination of lanthanides in natural waters and in biological samples.
authors.affiliation: Department of Chemistry, University of Idaho, Moscow, Idaho 83843, USA.
authors.forename: J
authors.initials: J
authors.lastname: Tang
authors.forename: C M
authors.initials: CM
authors.lastname: Wai