Spatially resolved δ13C measurements of solid samples via Laser Ablation Cavity Ringdown Spectroscopy (LA CRDS) – a new tool for environmental research

Cavity ringdown spectroscopy (CRDS) is a well-established technique used for measuring a large variety of gaseous species which are known to absorb light radiation at specific wavelengths, e.g., CO₂, CH₂, C₂H₄, water vapors, etc. In the field of environmental and geochemical research, CRDS is commonly used to determine the isotopic ratios of light isotope families, like hydrogen, carbon, oxygen, etc. Similarly, laser ablation (LA) is a solid sample introduction method which is used in conjunction with a variery of spectrometric and spectroscopic techniques and works by focusing a laser beam (of various wavelengths, pulse width and energy) onto the sample surface to convert minute amounts of the solid into fine aerosol, or gaseous phase.

Hyphenating the two techniques is a recent addition to the earth sciences tool set [1,2]. While still in its infancy, LA CRDS is a promising technique for fast, highly accurate and spatially resolved stable isotope measurements. In this contribution we look at the figures of merit of the technique when measuring δ¹³C, comparing different types of lasers (pulsed nanosecond solid state 213 nm wavelength, and continuously emitting infrared CO₂ laser) on both organic (wood, cellulose, plastics, and plant derived material) as well as inorganic matrices (soils, CaCO₃) which are critical proxies for environmental and climatic studies. We also investigate the impact of increased spatial resolution (i.e., tens of micron spot sizes) on the accuracy and precision of the analysis.

 

 

[1] Stremtan, C., Wozniak, J., Puscas, C. M., and Tamas, T.: Laser Ablation – Cavity Ring Down Spectrometry, a new method for the in-situ analysis of δ13C of organic and inorganic carbonates, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17192, https://doi.org/10.5194/egusphere-egu24-17192, 2024.

[2] E. Malegiannaki, P. Bohleber, D. Zannoni, C. Stremtan, A. Petteni, B. Stenni, C. Barbante, B.M. Vinther, V. Gkinis, Towards high-resolution water isotope analysis in ice cores using laser ablation - cavity ring-down spectroscopy, Anal. (2024) 5843–5855. https://doi.org/10.1039/d4an01054j.