title: Pre-concentration of rare earths using silica gel loaded with 1-(2-pyridylazo)-2-naphthol (PAN) and determination by energy dispersive X-ray fluorescence.
abstract: The determination of a single rare earth element in a mixture with other species of this family is a very challenging problem in analytical chemistry due to the close similarity of their chemical properties. In this work, a liquid-solid extraction procedure for praseodymium, neodymium, samarium and yttrium mixtures and subsequent determination by energy dispersive X-ray fluorescence spectrometry is described. The pre-concentration procedure, which involves the use of silica modified with 1-(2-pyridylazo)-2-naphthol, permits complete recovery of the rare earths and significant sensitivity enhancement in comparison with direct determination in the aqueous phase. Determinations in quaternary mixtures show typical precisions and accuracies of 3% and 5%, respectively.
authors.affiliation: Universidade Estadual de Campinas, Instituto de Quimica, C.P. 6154, 13083-970 Campinas-SP, Brazil.
authors.forename: L
authors.initials: L
authors.lastname: Cornejo-Ponce
authors.forename: P
authors.initials: P
authors.lastname: Peralta-Zamora
authors.forename: M I
authors.initials: MI
authors.lastname: Bueno