Advancing Tree-Ring Isotope Analysis: A Comparative Assessment of LA-CRDS and LA-IRMS

Stable isotope analysis of tree rings provides critical insight into past environmental and climatic conditions. Traditionally, the elemental analyzer has been the benchmark sample introduction peripheral for isotope ratio mass spectrometers (EA IRMS) for spatially resolved δ¹³C measurements in wood and cellulose. However, recent developments in using laser ablation as sample introduction peripheral for both the IRMS (LA-IRMS) and cavity ring-down spectroscopes (LA-CRDS) introduce promising alternatives that combine cost efficient, rapid analysis with high spatial resolution and simplified sample handling.

In this study, we present a comparative evaluation of LA-CRDS and LA-IRMS for δ¹³C measurements relevant to tree ring research. We examine figures of merit for LA-CRDS and LA-IRMS using pulsed nanosecond solid-state lasers at 213 nm wavelength (Teledyne Photon Machines) coupled via a dedicated ablation chamber (Terra Analitic) to a Picarro CO2 isotope analyzer (G2201-i) and Sercon HS2022 IRMS. Key performance indicators such as accuracy, precision, and spatial resolution are assessed to determine the suitability of both techniques for high-resolution tree-ring analysis.

Our findings highlight scenarios where each of these techniques offer advantages, such as faster throughput and reduced infrastructure requirements, while maintaining analytical rigor. These results underscore the growing potential of LA-IRMS and LA-CRDS as innovative tools for the tree-ring research community and broader environmental studies.

This advancement opens new opportunities for high-resolution dendrological studies, enabling a broader adoption of isotope-based research, including climate reconstructions, past and present environmental studies, and tracing anthropic activity.