Determination of actinides in environmental and biological samples using high-performance chelation ion chromatography coupled to sector-field inductively coupled plasma mass spectrometry

High-performance chelation ion chromatography, using a neutral polystyrene substrate dynamically loaded with 0.1 mM dipicolinic acid, coupled with sec tor-field inductively coupled plasma mass spectrometry has been successfull y used for the separation of the actinides thorium, uranium, americium, nep tunium and plutonium. Using this column it was possible to separate the var ious actinides from each other and from a complex sample matrix. In particu lar, it was possible to separate plutonium and uranium to facilitate the de tection of the former free of spectral interference. The column also exhibi ted some selectivity for different oxidation states of Np, Pu and U. Two ox idation states each for plutonium and neptunium were found, tentatively ide ntified as Np(V) and Pu(III) eluting at the solvent front, and Np(IV) and P u(IV) eluting much later. Detection limits were 12, 8, and 4 fg for (NP)-N- 237, Pu-239, and Am-241, respectively, for a 0.5 ml injection. The system w as successfully used for the determination of Pu-239 in NIST 4251 Human Lun g and 4353 Rocky Flats Soil, with results of 570 +/- 29 and 2939 +/- 226 fg g(-1), respectively, compared with a certified range of 227-951 fg g(-1) f or the former and a value of 3307 +/- 248 fg g(-1) for the latter. (C) 2001 Elsevier Science B.V. All rights reserved.