Measuring triple oxygen (16O, 17O and 18O) and carbon (12C, 13C) isotopes in small samples of carbon dioxide by laser spectroscopy

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I propose to spend 5 months at Harvard University developing and learning a new analytical method for measuring triple oxygen (16O, 17O, 18O) and carbon (12C, 13C) isotopes in small samples of CO2 produced from carbonate minerals using mid-infrared spectroscopy. The development will be conducted collaboratively with Prof. Daniel Schrag at the Harvard Center for the Environment (see letter of support) and Aerodyne Research, a private-sector company specializing in spectroscopy located in Billerica, Massachusetts, only 20 miles northwest of Boston. The method will permit the simultaneous analysis of 18O/16O, 13C/12C, and 17O/16O in CO2 in small samples of CO2 gas equivalent to microgram quantities of calcium carbonate with no spectral interferences. Laser spectroscopy offers a distinct advantage over conventional isotope ratio mass spectrometry (IRMS) for the measurement of isotopic ratios in CO2 because isobaric interferences on mass 45 precludes the direct measurement of 17O/16O by IRMS. This new approach will open new avenues of research for measuring 17O/16O in CO2 and carbonate minerals that has been hitherto difficult to measure by IRMS. The collaboration will lead to a proposal to acquire a similar system for the Godwin Laboratory at the University of Cambridge to keep the analytical facility at the forefront of innovative technology for stable isotope geochemistry.