A NEW MINIATURIZED EXTRACTION CHROMATOGRAPHY METHOD FOR PRECISE U-PB ZIRCON GEOCHRONOLOGY

Abstract

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, referred to as TRU.Spec and Sr.Spec, respectively. These afford a straightforward separation of U and Pb with high yield, good purity and satisfactory blank levels, on micro-columns using very small volume (5 μl) of mixed resins. Owing to the selectivity and high capacity of the specific extraction chromatographic materials for U and Pb, 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 fragments of the Zr91500 zircon standard.