Chemical Resolution of Pu+ from U+ and Am+ Using a Band-Pass Reaction Cell Inductively Coupled Plasma Mass Spectrometer

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• 作者：Scott D. Tanner ; Chunsheng Li ; Vladimir Vais ; Vladimir I. Baranov ; and Dmitry R. Bandura
• 刊名：Analytical Chemistry
• 出版年：2004
• 出版时间：June 1, 2004
• 年：2004
• 卷：76
• 期：11
• 页码：3042 - 3048
• 全文大小：210K
• 年卷期：v.76,no.11(June 1, 2004)
• ISSN：1520-6882

文摘

Determination of the concentration and distribution of thePu and Am isotopes is hindered by the isobaric overlapsbetween the elements themselves and U, generally requiring time-consuming chemical separation of the elements.A method is described in which chemical resolution ofthe elemental ions is obtained through ion-moleculereactions in a reaction cell of an ICPMS instrument. Thereactions of "natural" U⁺, ²⁴²Pu⁺, and ²⁴³Am⁺ withethylene, carbon dioxide, and nitric oxide are reported.Since the net sensitivities to the isotopes of an elementare similar, chemical resolution is inferred when oneisobaric element reacts rapidly with a given gas and theisobar (or in this instance surrogate isotope) is unreactiveor slowly reactive. Chemical resolution of the m/z 238isotopes of U and Pu can be obtained using ethylene as areaction gas, but little improvement in the resolution ofthe m/z 239 isobars is obtained. However, high efficiencyof reaction of U⁺ and UH⁺ with CO₂, and nonreaction ofPu⁺, allows the sub-ppt determination of ²³⁹Pu, ²⁴⁰Pu,and ²⁴²Pu (single ppt for ²³⁸Pu) in the presence of 7orders of magnitude excess U matrix without prior chemical separation. Similarly, oxidation of Pu⁺ by NO, andnonreaction of Am⁺, permit chemical resolution of theisobars of Pu and Am over 2-3 orders of magnituderelative concentration. The method provides the potentialfor analysis of the actinides with reduced sample matrixseparation.