High speed, high sensitivity LA sector field ICP-MS for U-Pb zircon geochronology

Abstract:

Laser ablation inductively coupled plasma mass spectrometry is one of the most popular and successful techniques available for U-Pb dating applications. The method allows fast sampling, high spatial resolution and good precision, with absolute U/Pb age resolution for zircon of ca. 1-2%, 2s [1].

Significant and continuous technological advances in both mass spectrometry and laser ablation systems support the development of increasingly efficient approaches aimed at reducing the volume of sampled material (hence allowing higher spatial resolution) and/or measurement time. This is particularly relevant for high throughput zircon detrital studies which typically require the analysis of tens of zircon samples, each including at least 100 single grain ablations [2 and references therein].

Here we explore the benefits of using an ESI NWR 193 ™ laser ablation system coupled with an Element XR ™ sector field ICP-MS equipped with a Dual Concentric Injector (DCI) ™ [3] and Jet Interface. The Jet Interface has proven to substantially increase the sensitivity in dry plasma [4]. The DCI minimizes aerosol dispersion for rapid, efficient sample transport and allows fast washout.

Our aim was to substantially reduce the duration of the individual measurements without compromising the final isotope ratio precision. We report U-Pb results for a variety of zircon reference materials and samples.

[1] Schaltegger et al. (2015) Chem. Geol.

[2] Sundell et al. (2020) Geostand. Geoanalytical Res.

[3] Douglas et al. (2015) Anal. Chem.

[4] Roberts et al. (2020) Thermo Fisher Scientific Application Note AN30685