Presentation + Paper
31 January 2020 Hollow fiber mid-IR spectrometer with UV laser ablation sampling for fine spatial resolution of isotope ratios in solids
Author Affiliations +
Abstract
We describe a system that combines isotope ratio analysis via mid-infrared (Mid-IR) laser absorption spectroscopy with fine spatial resolution sampling using a UV pulsed laser. The UV laser ablates a pit in a solid on the order of 10 microns in diameter. The sample-derived particulates resulting from laser ablation pass through a micro-combustor, and the resulting gas is analyzed using Mid-IR laser absorption spectroscopy in a capillary absorption spectrometer (CAS). The CAS uses a hollow fiber optic waveguide with a reflective inner coating and a small internal volume on the order of 1 ml. The hollow fiber both guides the laser light from source to detector and contains the gas sample at reduced pressure. Near unity overlap between the laser beam and sample enables sensitive analysis with ultra-small sample size. A prototype system has been demonstrated to enable stable carbon isotopic analysis (δ13C) with 1 per mil precision using < 1 picomole of carbon and is currently being used to study nutrient exchange in soil/root/microbial rhizosphere studies. The smaller sample size of this system is enabling fine spatial resolution analysis (on the order of 10 microns), which is roughly an order of magnitude smaller than was possible with an isotope ratio mass spectrometer (IRMS). In addition to rhizosphere studies, the system can provide a useful tool for fine scale isotope analysis with applications in biological, forensic, and environmental science.
Conference Presentation
© (2020) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Jason Kriesel, Camille Makarem, Andrew Fahrland, James Moran, Timothy Linley, and James Kelly "Hollow fiber mid-IR spectrometer with UV laser ablation sampling for fine spatial resolution of isotope ratios in solids", Proc. SPIE 11288, Quantum Sensing and Nano Electronics and Photonics XVII, 112881Z (31 January 2020); https://doi.org/10.1117/12.2546908
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KEYWORDS
Laser ablation

Carbon

Solids

Biological research

Laser spectroscopy

Mid-IR

Spatial resolution

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