A new miniaturized extraction chromatography method for precise U-Pb zircon geochronology

In this paper, we describe a new method for the concomitant separation of U and Pb in zircons for radiometric dating purposes. The proposed separation scheme is based on a blend of two extraction chromatographic materials, re ferred to as TRU.Spec and Sr.Spec, respectively. These afford a straightfor ward separation of U and Pb with high yield, good purity and satisfactory b lank levels, on micro-columns using very small volume (5 mul) of mixed resi ns. Owing to the selectivity and high capacity of the specific extraction c hromatographic materials for U and ph, this new technique could be further scaled-down. The validity of the method is illustrated by measurements of U /Pb isotopic ratios and determination of corresponding ages in 0.2-0.8 mg f ragments of the Zr91500 zircon standard. (C) 2001 Elsevier Science B.V. All rights reserved.